The Odessa Catacombs in Ukraine are the world's largest underground labyrinth, stretching up to 2,500 kilometers (1,600 miles) long and 40 meters deep...

Floor to ceiling bones, stacked in geometric patterns for 1,600 miles...125 feet deep... How many bodies do you think that'd take?

These catacombs are all over the world... and they built churches on top of them.

Just stop and think about that for a moment...

Part 1

Part 2

Part 3

The Odessa Catacombs in Ukraine are the world's largest underground labyrinth, stretching up to 2,500 kilometers (1,600 miles) long and 40 meters deep...

Floor to ceiling bones, stacked in geometric patterns for 1,600 miles...125 feet deep... How many bodies do you think that'd take?

Just stop and think about that for a moment...