Cats sleep up to eighteen hours a day, but never quite as deep as humans. Instead, they fall asleep quickly and wake up intermittently to check to see if their environment is still safe.

John Van Wormer invented paper milk cartons after dropping a bottle of milk one morning. The bottle broke spilling the milk everywhere. That annoyance was enough for Van Wormer to come up with the idea.

San Francisco cable cars are the only National Monuments that move.

AMAZING FACTS