Archaeologists found everything from food still on tables to detailed wall paintings and even the outlines of people caught in the disaster.

The city features incredible stone buildings that fit together so perfectly you can't even slip a piece of paper between them!

Scientists think earthquakes and flooding caused the city to sink about 1,200 years ago.

It was home to around 100,000 people before being abandoned around 900 CE.

The city's giant temples are so tall they're called "sky-scrapers of the Maya."

The famous Angkor Wat temple is just one of hundreds of temples in the area. The city was gradually abandoned in the 1400s.

The people who built them suddenly left around 1300 CE. Drought and resource depletion might have forced them to move, but the full story remains a mystery.

It was the capital of a wealthy trading empire but was abandoned around 1500 CE.

Some walls are 36 feet tall and 20 feet thick!

The city declined after trade routes changed and earthquakes damaged its water system.

It was built around 1200 CE using massive basalt logs, some weighing up to 50 tons!

The city was abandoned around 1628 CE for mysterious reasons.

They discovered not just one city, but nine cities built on top of each other over thousands of years!

It goes 18 stories deep and includes rooms for living, storage, religious gatherings, and even livestock.

It was discovered when a man kept losing his chickens to a hole in the wall… he went to find them and discovered a lost city!

Mohenjo-Daro remains shrouded in mystery, as scholars continue to investigate its sophisticated social structure, trade practices, and the reasons behind its eventual decline.

The city was so wealthy that people called it "the heaven of abundance." It disappeared after being conquered and was lost until the 1980s.

While much of it lies buried under modern settlements, archaeologists have found incredible statues, including a 33-foot limestone statue of Ramesses II.

Nobody knows who built this city or why they abandoned it around 750 CE, but even the later Aztecs were amazed by its size.

The city mysteriously declined around 900 CE, leaving behind amazing art that helps us understand Maya culture.

Its ruins include 6,000 structures, with pyramids rising above the rainforest canopy.

The city's ruins show how Thai art and architecture developed their unique style.

The city was abandoned in 1565 after being attacked by rival kingdoms.

Located near modern-day St. Louis, Cahokia was bigger than London in 1250 CE! Native Americans built huge earth mounds here, including one that's 100 feet high. The city had a wooden circle of posts used to track the seasons, sometimes called "America's Stonehenge."