From the www--information I'm sure you will find fascinating at this time:

"5... 4... 3... 2... 1... Liftoff, that's the countdown for a space shuttle leaving the Earth. The flea when jumping accelerates 50 times faster than a space shuttle. Although fleas cannot fly, they can jump over seven inches high and thirteen inches long, that is about one hundred and fifty times its own length. Without its outer shell it would get smashed by the velocity of the jump, and especially on its landing. Fleas have a well built body for jumping. Did you know that if fleas were the size of humans, they would be able to jump over the St. Paul's Cathedral in London six hundred times for three days!"