This forest city was founded in the 9th century and has a unique plan of stone pathways, plazas, and houses.
A five-day trek to Ciudad Perdida is an adventure by itself, meeting the indigenous Kogi and Wiwa people, who are some of the modern-day guardians.

Ciudad Perdida, Colombia

Excavations of the site on Crete began in 1900. 
Travelers can view the remains of the Minoan palace at Knossos. The palace's east wing is adorned with a fresco that depicts three figures and a giant vaulting bull.

Knossos, Greece

Persepolis was built in the 6th century B.C.E. Achaemenid Empire kings fortified a natural stone terrace and turned the landscape to an inspiring effect and military advantage.
After centuries, the delicate carvings, inscriptions, and palaces of Persepolis were excavated in the 20th century. Travelers can see 13 of the original 72 towering stone columns.

Persepolis, Iran

Machu Picchu was a sanctuary for the Inca before the fall of the Inca Empire in the 16th century.
The remnant fortifications were rediscovered in 1911. Journey to Machu Picchu, then trek to the neighboring peak of Huayna Picchu for views across the main site.

Machu Picchu, Peru

The ancient Maya city of El Mirador, which dates back to 1,000 B.C.E., will only be reached by the adventurous few.
There are two ways to get there: A helicopter or trek two days from the road's end at the village of Carmelita. Once there, you can climb La Danta, a towering pyramid.

El Mirador, Guatemala

Ubar was a trading post deep in the desert. It was lost to the blowing sand for nearly 1,000 years and found in 1992 using images taken from space.
Ubar is located on the southernmost edge of Oman, two hours inland from the Arabian Sea city of Salalah.

Ubar, Oman

In 79 C.E., ash from Mount Vesuvius covered and buried Pompeii and Herculaneum for nearly 17 centuries.
Taking a walk through the cities, which are about a 20-minute drive apart, to see frescoes, visit the ancient brothel, see the petrified bodies and the Temple of Apollo.

Pompeii and Herculaneum, Italy

Petra was carved by Nabateans and is an attraction in Jordan.
The entrance is leading visitors from a shadowy gorge to views of soaring, tangerine-colored rock. Climbing a steep pathway will reveal the High Place of Sacrifice - it's pair of huge obelisks is believed to represent Nabatean gods.

Petra, Jordan

Troy has a 4,000-year history. Archeologist Heinrich Schliemann used Homer's Iliad like a treasure map and found the site in 1870.
Troves the ancient fortifications and palaces once held are available for viewing in the Troy museum.

Troy, Turkey

Xanadu was a city of the Mongolian and Han cultures, where Kublai Khan ruled.
It is located about five hours northwest of Beijing. Travelers can visit the remains of the excavated temples, stone walls, and tombs of that cosmopolitan capital.

Xanadu, China

Residents abandoned the site with its stone pyramids in the 11th century.
Rediscovered in 1938, it's architectural achievements are impressive: Caana, the temple complex at the heart of Caracol, remains the tallest structure in the country at 141 feet.

Caracol, Belize

Photo by Matyas Rehak/Shutterstock Rediscover these abandoned cities by traveling to see their ruins, where you can readily imagine their lost-to-time structures and civilizations.