Doors -

: Located at NASA’s Vehicle Assembly Building in Florida, these four doors are 456 feet high and take approximately 45 minutes to fully open or close.

: Invented in the 1st century AD by Heron of Alexandria , this early steam-powered mechanism used heat from a temple fire to trigger a series of pulleys that opened the doors. : Located at NASA’s Vehicle Assembly Building in

Doors are much more than simple barriers; they are complex architectural elements with a history spanning over 5,000 years, ranging from ancient stone gateways to high-tech NASA portals. : Discovered in Zurich, Switzerland, archaeologists found a

: Discovered in Zurich, Switzerland, archaeologists found a wooden door estimated to be over 5,100 years old . : In New York, it is technically illegal

: The earliest "doors" were likely large rocks or animal hides. By 3,000 BCE, Egyptians were using single-piece wooden doors for tombs.

: In New York, it is technically illegal for a revolving door to rotate faster than 15 rotations per minute to maintain safety.