The ruins of Machu Picchu in Peru are breathtaking. Constructed by the Incas in the 1400s, this stone city sits perched atop the Andes Mountains, almost 8,000 feet above sea level overlooking the Urubamba River. Erosion has set in as hordes of tourists trek around the ruins, and there's no telling if this wondrous site will hold up over time.
Stonehenge is a prehistoric monument in the countryside of England. Archaeologists and historians still debate the true origins of these mysterious stone megaliths. Tourists must observe this marvel from a short distance so as not to deteriorate the site.
Pyramids at Giza
The Pyramids at Giza, constructed as monuments to Egyptian kings roughly 4,600 years ago, are the only surviving wonders of the ancient world. The Great Pyramid of Khufu measures 480 feet in height, covering an area of more than 12 acres. The pyramids have worn down gradually over time, with erosion and tomb-robbers chipping away at them.
The Taj Mahal
The Taj Mahal was built in the 1600s by the Mogul emperor as a shrine for his deceased queen. The palace is a lovely combination of Hindi, Persian, Mogul and Islamic architecture. Visitors wander the symmetrical marble corridors, tour the pristine gardens and look up at the striking minarets at the corners of the building. Air pollution and corrosion have already started to damage the palace, and the Indian government is looking to counteract this problem.
The Amazon Rain Forest
The Amazon rain forest in South America is immense, extending into Brazil, Peru and seven other countries. The Amazonian flora and fauna are diverse and unique. Tourists can boat down the powerful Amazon River and explore the lush jungle trails and regional settlements. Unfortunately, Greenpeace estimates that the Amazon will disappear due to deforestation in the next 80 years if industry there continues at the current rate.
Old City of Jerusalem
The Old City of Jerusalem is one of the holiest places in the world. With three major religions claiming old Jerusalem as home, the region has seen more than its share of turmoil over the centuries. Visit ancient religious sites such as the Dome of the Rock, the Wailing Wall, and the hillside where Jesus Christ is said to have been crucified. Christians, Jews and Muslims have fought over this land constantly. Corrosion and erosion aside, it is hard to predict how long the Old City of Jerusalem will last if full-scale war ensues.
Easter Island is a remote piece of land in the South Pacific Ocean, home to roughly 1,000 stone statues known as moai. These human-shaped statues were carved by ancient inhabitants using volcanic rock. Rising ocean waters and storms from global warming may eventually signal the end for Easter Island, but for now travelers can still catch a glimpse of these ancient Polynesian works of art.