Originally named Teyuna by the Tairona peoples, Ciudad Perdida (Spanish for “Lost City”) was renamed after it was rediscovered in 1972 by a group of local treasure hunters, who found a series of stone steps rising up a mountainside and followed them to the abandoned city. The impressive city is believed to have been founded in approximately 800 CE, more than 600 years earlier than Machu Picchu.

Madurai has been continuously inhabited since 500 BCE, and the city still boasts stunning Dravidian architecture dating back to that period. Madurai was designed in the shape of a lotus, which symbolizes the goddess Lakshmi, and the city also boasts an impressive Meenakshi Amman Temple complex at its center, featuring impressive pyramidal structures known as “Gopurams.”

Cusco — located high in the Andes Mountains and once the capital of the Inca Empire — was said to be designed in the shape of a puma, symbolizing the power of the Earth. The puma’s head was the temple of Saqsaywaman, two rivers outlined the body, and the city’s main plaza — Hawkaypata — was located in the belly.

Cahokia, the largest pre-Columbian settlement north of Mexico, was located eight miles northeast of present-day St. Louis. Settled between 800 and 1400 CE, the site once covered up to 4,000 acres and was home to as many as 20,000 peoples of the Mississippian culture. The ancient city declined in 1400 and was slowly abandoned for reasons that remain a mystery.

Found across the deserts of modern-day Iran, yakhchāls appear almost like giant clay beehives. Introduced around 400 BCE, the conical structures were used by ancient Persians as evaporation coolers, making and collecting ice during the colder months and storing it throughout the year to preserve food — long before electricity was invented.

Located 30 miles from Mexico City, Teotihuacan was once a prosperous Mesoamerican city. The area was settled sometime around 400 CE, but it was then abandoned, until the Aztecs found it in the 1400s and called it Teotihuacan (“the place where the gods were created”). The city includes several important structures, including the Pyramid of the Moon and the Temple of Quetzalcoatl.

The world’s largest religious structure, the Buddhist temple known as Angkor Wat was built by Emperor Suryavarman II to serve as the political center of the Khmer Empire. The word “Angkor” means “capital city” in the Khmer language. Angkor Wat was originally constructed as a Hindu temple, though by the end of the 12th century it had transformed into a Buddhist site.

The Walls of Jericho date back to at least 8000 BCE, making them the oldest known set of human-made city walls. The walls were constructed to be nearly 12 feet high and six feet wide at their base. The Jericho settlement — located today in the West Bank — also boasted a 28-foot-tall stone tower, often referred to as the world’s first skyscraper.

Pompeii wasn’t the only ancient city struck by the eruption of Mount Vesuvius, which bathed the surrounding Roman cities in lava, ash, and mud in 79 CE. Herculaneum was buried in 60 feet of mud and ash, preserving everything in the city, right down to a library full of manuscripts. Rediscovered in 1738, Herculaneum’s ruins are still being excavated today.

The Great Ziggurat of Ur was constructed around 2100 BCE by King Ur-Nammu to honor the moon goddess Nanna, whose temple once stood atop the structure (though it has since fallen into ruins). At its peak, the ziggurat featured three terraces situated on a massive rectangular lower level that’s estimated to have taken 720,000 bricks to build.

Known in ancient times as Mutul, the modern-day Guatemalan city of Tikal was once a thriving Maya metropolis that flourished from around 600 BCE to 900 CE. At its peak, Tikal covered an area of 50 square miles and boasted over two dozen pyramids, as well as an estimated 45,000 to 62,000 residents.

Peru is located in a seismic zone, and to protect against potential earthquakes, the Incas made the buildings of the ancient citadel of Machu Picchu with precisely fit stones, held together by gravity alone. Nothing so thin as a credit card could be inserted in the cracks, allowing the mortar-free stones to “dance” during an earthquake, only to resettle back into place once it ended.

Two-thousand years ago, when Beijing was just a provincial city and Shanghai a fishing village, the most important city in China was Xi’an. Located in the central part of the country, Xi’an was China’s first capital, established in 202 BCE and lasting through 10 dynasties. It was the eastern terminus of the Silk Road, an important ancient trading route connecting Rome, Italy, to China.

Carthage was a key trading port on the coast of what is now Tunisia, and its strategic location allowed the Cartheginians to control sea traffic through the Mediterranean Sea between Sicily and Africa. Founded in 814 BCE, the city thrived for centuries before falling in the Punic Wars in 146 BCE. In 1979, UNESCO added the archaeological ruins of Carthage to its World Heritage List.

One of the most remarkable remnants of the ancient world, the rock-carved ruins of Petra can be found deep in the desert of Jordan. It is believed that Petra was inhabited as early as 9000 BCE but was later abandoned. Its buildings fell into ruin, hidden by the surrounding canyons, until Swiss explorer Jean Louis Burckhardt became the first outsider to visit the region in 1812.

Also known as the Pharos of Alexandria, the ancient Lighthouse of Alexandria was one of the Seven Wonders of the Ancient World. Completed around 280 BCE during the reign of Ptolemy II, the lighthouse stood around 350 feet high. It was likely the tallest human-made structure in the world at the time, aside from the pyramids at Giza, but it was later destroyed by earthquakes.

Located on the Yucatán peninsula in modern-day Mexico, Chichén Itzá was once a thriving and powerful city of the Maya civilization before it fell into decline around the year 1000 CE. Today, the most famous site in Chichén Itzá is El Castillo, or the Temple of Kukulkan, which is one of the city’s many stone pyramids that attract millions of visitors annually.

Troy, located on the northwest coast of modern-day Turkey, was first settled around 3000 BCE. The city is famous in Greek mythology as the site of the Trojan War and was featured in Homer’s “The Iliad.” Although much of the ancient city has been lost over the years, visitors can still see sites like the Temple of Athena, the South Gate, and the Mycenaean Houses.

In Greek, akron means “high point” and polis means “city.” When you combine the two words and take into account the site’s hilltop location, it’s not hard to see why the Acropolis of Athens was so named. However, in ancient times, this part of Athens was more commonly known as Cecropia. The name honors the first Athenian king, Cecrops, a mythical figure who was part man, part serpent.

The fact that Memphis, Tennessee, shares a name with the ancient capital of Egypt is no coincidence. Memphis was the ancient capital of Egypt because of its prominent location on the Nile River Delta. Its American counterpart was also located on the delta of an important river — the Mississippi, which was sometimes referred to as “the American Nile.”

Situated about 60 miles south of Baghdad, the ancient city of Babylon was founded more than 4,000 years ago and became the center of Mesopotamia civilization for almost 2,000 years. The ancient city was home to important scientific discoveries in trigonometry, physics, and astronomy. Babylon’s ruins are still present along the east bank of the Euphrates River.