Total surveyed passage length676,000 m
9,562Boeing 747 lengths
3.6 millionToothbrushes
Over 676 km and still growing with new discoveries
Photo from Wikimedia Commons
Mammoth Cave
The longest known cave system on Earth/Landforms
Mammoth Cave in Kentucky has over 676 kilometers of surveyed passageways, making it the longest known cave system in the world by a huge margin -- more than twice the length of the second longest. New passages are still being discovered, so the true length keeps growing. The cave formed in limestone over the last 10 million years, carved by mildly acidic groundwater.
Measurements
Maximum depth116 m
64.4Bookcase heights
2,297AA battery lengths
9.67House widths
Vertical extent from highest to lowest point
Longest single passage13,000 m
3,939Hammock lengths
2.8 quintillionIron nuclei
Some individual passages stretch over 13 km
Interior temperature287 K
1.04Refrigerators
6.4 tenthsBaking ovens
8.4 tenthsSun-baked car interiors
A constant 14 degrees C year-round deep in the cave
Approximate age315 trillion s
315 quadrillionCamera shutters
1.3 septillionProcessor cycles
Primary formation began roughly 10 million years ago
Tallest passage height58 m
6.1 quadrillionthsLight-years
5.5 tenthsSoccer pitches
Some chambers are impressively tall