Pathophysiology
The mesothelium consists of a single layer of flattened to cuboidal cells forming the epithelial lining of the serous cavities of the body including the peritoneal, pericardial and pleural cavities. Deposition of asbestos fibers in the parenchyma of the lung may result in the penetration of the visceral pleura from where the fiber can then be carried to the pleural surface, thus leading to the development of malignant mesothelial plaques. The processes leading to the development of peritoneal mesothelioma remain unresolved, although it has been proposed that asbestos fibers from the lung are transported to the abdomen and associated organs via the lymphatic system. Additionally, asbestos fibers may be deposited in the gut after ingestion of sputum contaminated with asbestos fibers.
Pleural contamination with asbestos or other mineral fibers has been shown to cause cancer. Long thin asbestos fibers (blue asbestos, amphibole fibers) are more potent carcinogens than "feathery fibers" (chrysotile or white asbestos fibers).[10] However, there is now evidence that smaller particles may be more dangerous than the larger fibers. They remain suspended in the air where they can be inhaled, and may penetrate more easily and deeper into the lungs. "We probably will find out a lot more about the health aspects of asbestos from [the World Trade Center attack], unfortunately," said Dr. Alan Fein, chief of pulmonary and critical-care medicine at North Shore-Long Island Jewish Health System. Dr. Fein has treated several patients for "World Trade Center syndrome" or respiratory ailments from brief exposures of only a day or two near the collapsed buildings.
Mesothelioma development in rats has been demonstrated following intra-pleural inoculation of phosphorylated chrysotile fibers. It has been suggested that in humans, transport of fibers to the pleura is critical to the pathogenesis of mesothelioma. This is supported by the observed recruitment of significant numbers of macrophages and other cells of the immune system to localized lesions of accumulated asbestos fibers in the pleural and peritoneal cavities of rats. These lesions continued to attract and accumulate macrophages as the disease progressed, and cellular changes within the lesion culminated in a morphologically malignant tumor.
Experimental evidence suggests that asbestos acts as a complete carcinogen with the development of mesothelioma occurring in sequential stages of initiation and promotion. The molecular mechanisms underlying the malignant transformation of normal mesothelial cells by asbestos fibers remain unclear despite the demonstration of its oncogenic capabilities. However, complete in vitro transformation of normal human mesothelial cells to malignant phenotype following exposure to asbestos fibers has not yet been achieved. In general, asbestos fibers are thought to act through direct physical interactions with the cells of the mesothelium in conjunction with indirect effects following interaction with inflammatory cells such as macrophages.
Analysis of the interactions between asbestos fibers and DNA has shown that phagocytosed fibers are able to make contact with chromosomes, often adhering to the chromatin fibers or becoming entangled within the chromosome. This contact between the asbestos fiber and the chromosomes or structural proteins of the spindle apparatus can induce complex abnormalities. The most common abnormality is monosomy of chromosome 22. Other frequent abnormalities include structural rearrangement of 1p, 3p, 9p and 6q chromosome arms.
Common gene abnormalities in mesothelioma cell lines include deletion of the tumor suppressor genes:
Neurofibromatosis type 2 at 22q12
P16INK4A
P14ARF
Asbestos has also been shown to mediate the entry of foreign DNA into target cells. Incorporation of this foreign DNA may lead to mutations and oncogenesis by several possible mechanisms:
Inactivation of tumor suppressor genes
Activation of oncogenes
Activation of proto-oncogenes due to incorporation of foreign DNA containing a promoter region
Activation of DNA repair enzymes, which may be prone to error
Activation of telomerase
Prevention of apoptosis
Asbestos fibers have been shown to alter the function and secretory properties of macrophages, ultimately creating conditions which favour the development of mesothelioma. Following asbestos phagocytosis, macrophages generate increased amounts of hydroxyl radicals, which are normal by-products of cellular anaerobic metabolism. However, these free radicals are also known clastogenic and membrane-active agents thought to promote asbestos carcinogenicity. These oxidants can participate in the oncogenic process by directly and indirectly interacting with DNA, modifying membrane-associated cellular events, including oncogene activation and perturbation of cellular antioxidant defences.
Asbestos also may possess immunosuppressive properties. For example, chrysotile fibres have been shown to depress the in vitro proliferation of phytohemagglutinin-stimulated peripheral blood lymphocytes, suppress natural killer cell lysis and significantly reduce lymphokine-activated killer cell viability and recovery. Furthermore, genetic alterations in asbestos-activated macrophages may result in the release of potent mesothelial cell mitogens such as platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β) which in turn, may induce the chronic stimulation and proliferation of mesothelial cells after injury by asbestos fibres.

Screening
There is no universally agreed protocol for screening people who have been exposed to asbestos. Screening tests might diagnose mesothelioma earlier than conventional methods thus improving the survival prospects for patients. The serum osteopontin level might be useful in screening asbestos-exposed people for mesothelioma. The level of soluble mesothelin-related protein is elevated in the serum of about 75% of patients at diagnosis and it has been suggested that it may be useful for screening.[6] Doctors have begun testing the Mesomark assay which measures levels of soluble mesothelin-related proteins (SMRPs) released by diseased mesothelioma cells.

Diagnosing mesothelioma is often difficult, because the symptoms are similar to those of a number of other conditions. Diagnosis begins with a review of the patient's medical history. A history of exposure to asbestos may increase clinical suspicion for mesothelioma. A physical examination is performed, followed by chest X-ray and often lung function tests. The X-ray may reveal pleural thickening commonly seen after asbestos exposure and increases suspicion of mesothelioma. A CT (or CAT) scan or an MRI is usually performed. If a large amount of fluid is present, abnormal cells may be detected by cytopathology if this fluid is aspirated with a syringe. For pleural fluid, this is done by thoracentesis or tube thoracostomy (chest tube; for ascites, with paracentesis or ascitic drain; and for pericardial effusion with pericardiocentesis. While absence of malignant cells on cytology does not completely exclude mesothelioma, it makes it much more unlikely, especially if an alternative diagnosis can be made (e.g. tuberculosis, heart failure). Unfortunately, the diagnosis of malignant mesothelioma by cytology alone is difficult, even with expert pathologists.

Chichen Itza large pre-Columbian archaeological site built by the Maya civilization located in the northern center of the Peninsula, in the Yucatán state, present-day Mexico.
Chichen Itza was a major focal point in the northern Maya lowlands from the Late Classic through the Terminal Classic and into the early portion of the Early Postclassic period. The site exhibits a multitude of architectural styles, from what is called “Mexicanized” and reminiscent of styles seen in central Mexico to the Puuc style found among the Puuc Maya of the northern lowlands. The presence of central Mexican styles was once thought to have been representative of direct migration or even conquest from central Mexico, but most contemporary interpretations view the presence of these non-Maya styles more as the result of cultural diffusion.
The ruins of Chichen Itza are federal property, and the site’s stewardship is maintained by Mexico’s Instituto Nacional de Antropología e Historia (National Institute of Anthropology and History, INAH). The land under the monuments had been privately-owned until March 29, 2010, when it was purchased by the state of Yucatan

Machu Picchu Is a pre-Columbian Inca site located 2,430 metres (7,970 ft) above sea level. It is situated on a mountain ridge above the Urubamba Valley in Peru, which is 80 kilometres (50 mi) northwest of Cusco and through which the Urubamba River flows. Most archaeologists believe that Machu Picchu was built as an estate for the Inca emperor Pachacuti (1438–1472). Often referred to as "The Lost City of the Incas", it is perhaps the most familiar icon of the Inca World.
The Incas started building the estate around AD 1400 but it was abandoned as an official site for the Inca rulers a century later at the time of the Spanish conquest of the Inca Empire. Although known locally, it was unknown to the outside world before being brought to international attention in 1911 by the American historian Hiram Bingham. Since then, Machu Picchu has become an important tourist attraction.
Machu Picchu was declared a Peruvian Historical Sanctuary in 1981 and a UNESCO World Heritage Site in 1983. Since it was not plundered by the Spanish when they conquered the Incas, it is especially important as a cultural site and is considered a sacred place.
Machu Picchu was built in the classical Inca style, with polished dry-stone walls. Its primary buildings are the Intihuatana, the Temple of the Sun, and the Room of the Three Windows. These are located in what is known by archaeologists as the Sacred District of Machu Picchu. In September 2007, Peru and Yale University reached an agreement regarding the return of artifacts which Hiram Bingham had removed from Machu Picchu in the early twentieth century.

Christ the Redeemer Is a statue of Jesus Christ in Rio de Janeir, Brazil; considered the largest Art Deco statue in the world. The statue is 39.6 metres (130 ft) tall, including its 9.5 meter (31 feet) pedestal, and 30 metres (98 ft) wide. It weighs 635 tons (700 short tons), and is located at the peak of the 700 metres (2,300 ft) Corcovado mountain in the Tijuca Forest National Park overlooking the city. It is one of the tallest of its kind in the world. The statue of Cristo de la Concordia in Cochabamba, Bolivia, is slightly taller, standing at 40.44 metres (132.7 ft) tall with its 6.24 metres (20.5 ft) pedestal and 34.20 metres (112.2 ft) wide. A symbol of Christianity, the statue has become an icon of Rio and Brazil. It is made of reinforced concrete and soapstone.

Petra Is a historic and archaeologica city in the Jordanian governorate of Ma'an that has rock cut architecture and water conduits system. Established sometime around the 6th century BC as the capital city of the Nabataeans it is a symbol of Jordan as well as its most visited tourism attraction. It lies on the slope of Mount Hor in a basin among the mountains which form the eastern flank of Arabah (Wadi Araba), the large valley running from the Dead Sea to the Gulf of Aqaba. Petra is an UNESCO World Heritage Site since 1985.
The site remained unknown to the Western world

until 1812, when it was introduced by Swiss explorer Johann Ludwig Burckhardt. It was described as "a rose-red city half as old as time" in a Newdigate Prize-winning sonnet by John William Burgon. UNESCO has described it as "one of the most precious cultural properties of man's cultural heritage. Petra was chosen by the BBC as one of "the 40 places you have to see before you die

Great Wall of China Is a series of stone and earthen fortifications in northern China, built originally to protect the northern borders of the Chinese Empire against intrusions by various nomadic groups such as the Xiongnu from the north and rebuilt and maintained between the 5th century BC and the 16th century. Since the 5th century BC, several walls have been built that were referred to as the Great Wall. One of the most famous is the wall built between 220–206 BC by the first Emperor of China, Qin Shi Huang. Little of that wall remains; the majority of the existing wall was built during the Ming Dynasty.

The Great Pyramid Is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact. It is believed the pyramid was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu (Cheops in Greek) and constructed over a 20-year period concluding around 2560 BC. The Great Pyramid was the tallest man-made structure in the world for over 3,800 years. Originally the Great Pyramid was covered by casing stones that formed a smooth outer surface; what is seen today is the underlying core structure. Some of the casing stones that once covered the structure can still be seen around the base. There have been varying scientific and alternative theories about the Great Pyramid's construction techniques. Most accepted construction hypotheses are based on the idea that it was built by moving huge stones from a quarry and dragging and lifting them into place.

Taj Mahal is regarded as one of the eight wonders of the world, and some Western historians have noted that its architectural beauty has never been surpassed. The Taj is the most beautiful monument built by the Mughals, the Muslim rulers of India. Taj Mahal is built entirely of white marble. Its stunning architectural beauty is beyond adequate description, particularly at dawn and sunset. The Taj seems to glow in the light of the full moon. On a foggy morning, the visitors experience the Taj as if suspended when viewed from across the Jamuna river.Taj Mahal was built by a Muslim, Emperor Shah Jahan (died 1666 C.E.) in the memory of his dear wife and queen Mumtaz Mahal at Agra, India. It is an "elegy in marble" or some say an expression of a "dream." Taj Mahal (meaning Crown Palace) is a Mausoleum that houses the grave of queen Mumtaz Mahal at the lower chamber. The grave of Shah Jahan was added to it later. The queen’s real name was Arjumand Banu. In the tradition of the Mughals, important ladies of the royal family were given another name at their marriage or at some other significant event in their lives, and that new name was commonly used by the public. Shah Jahan's real name was Shahab-ud-din, and he was known as Prince Khurram before ascending to the throne in 1628