Photo Gallery The 21 Finalists
The Sydney Opera House is by far the most famous building in all of Australia. The light arching sails are a thing of beauty -- and its construction impressive. The roof is made with over a million ceramic tiles.
The Taj Mahal was built from 1630 to 1648 by Mughal Emperor Shah Jahan for his wife Mumtaz-i-Mahal. The temple is erected on a 100 meter by 100 meter marble platform -- the four minarets are each tilted slightly away from the mausoleum so that, should they fall, they won't damage the main structure.
Timbuktu in the West African country of Mali literally means the well of the Buktu. The old town was declared a UNESCO World Heritage Site in 1988 but continues to be threatened by desertification.
The Haghia Sophia in Istanbul was built in the 6th century as a Christian Church. When the Ottomans arrived in the 15th century, it was converted into a mosque and the minarets were built. Now, it is a museum and is considered a masterpiece of Byzantine architecture.
The Otowasan Kiyomizudera in eastern Kyoto is perhaps the best-known site in the city and in Japan. The buildings date to the 17th century, but the site has hosted a temple since 798.
The Kremlin in Moscow, including its myriad churches and palaces, is the historical center of the Russian capital. The site used to serve as the residence of the Russian czars.
The ruins of Machu Picchu were rediscovered in 1911, but it is thought that the Inca city was originally built in the 15th century. Its site, some 7,700 feet up in the mountains of Peru, provides visitors to the ruins with a stunning view. The buildings are built of stone blocks.
Neuschwanstein castle in southern Germany is the stuff of fairy tales. Built by King Ludwig II -- often called Crazy King Ludwig -- in the latter half of the 19th century, the castle was rarely used by him or his family; but it was the model for the Sleeping Beauty Castle at Disneyland.
The ancient town of Petra was carved out of stone cliffs in what is now Jordan. From the 3rd century BC until 100 A.D. the city was the capital of the Arab-speaking Nabataeans. The city became wealthy by controlling much of the trade in the region.
The Pyramids in Egypt represent the only site left over from the Seven Wonders of the Ancient World. Built some 2,500 years before Christ, the structures are considered not only the most famous sites in the region, but are perhaps the best-known cultural monuments in the entire world.
The Statue of Liberty at the entrance to New York Harbor was erected only in the late 1800s, but quickly became the most widely recognized symbol of freedom in the world. Some 46 meters high, it was a gift to the United States by France in 1886.
Stonehenge, located in the English county of Wiltshire, was likely erected between 2,500 B.C. and 2,000 B.C. -- but the site could be much older. It was added to the UNESCO list of World Heritage Sites in 1986. Exactly how the structure was built remains a mystery.
The Acropolis overlooks the Greek capital city of Athens. The Parthenon and other buildings which are today considered part of the ancient site were built during the Golden Age of Athens in the 5th century B.C.
The Alhambra in Granada, Spain, consists of a huge fortress complex complete with palaces, mosques and walls. The site was built between 1248 and 1354 by Muslim rulers of the region. Christians began to alter the buildings after conquering Grenada in 1492. The buildings are still considered one of the finest examples of Moorish architecture in the world.
Angkor Wat in Cambodia is the world's largest complex of temples. The site was the residence and sacred center for Khmer royalty between the 9th and 15th centuries. It was a world metropolis in the year 1000, with around a million residents.
Chichén Itzá is located on the Yucatan Peninsula in Mexico. Founded between 435 and 455, it eventually became one of the Mayans' most powerful cities. Civil war led to a long, slow decline in the 13th century.
The statue of Christ the Redeemer presides over Rio de Janeiro, Brazil, from the peak of Corcovado Mountain. The 125-foot-tall statue was inaugurated in 1931 and just celebrated its 75th anniversary in October.
The Colosseum in Rome has been one of the city's defining monuments since it was built in the 1st century A.D. With a capacity of 50,000, it was the largest amphitheater in the ancient world. The building remained in use for fully 500 years -- surviving the Roman Empire.
The gigantic stone heads of Easter Island (or Rapa Nui, in Tahitian) are among the most famous symbols of Polynesia. The 887 statues were likely carved between 1100 and 1600 and are called Moais.
The Eiffel Tower in Paris was erected between 1887 and 1889 by Alexandre Gustave Eiffel. The 300-meter-tall radio tower was built to commemorate the 100th anniversary of the French Revolution.
At over 6,000 kilometers long, the Great Wall of China is the longest system of walls in the world. Different chunks of the wall were built at different times and in different styles. The longest, continuous section is 2,500 kilometers long.
