A great and endlessly entertaining Reddit thread asks for weird facts that sound made up, but aren't, like "The Ottoman Empire still existed the last time the Cubs won the World Series" and "When you get a kidney transplant, they usually just leave your original kidneys in your body and put the 3rd kidney in your pelvis." And:
The United States in World War 2 created a bomb that used bats. The bats would be carrying small incendiary charges and would be released from the bomb in mid air, causing them to fly and scatter to different buildings in the area. The charges would then detonate and set all the buildings on fire. It was tested and proven to be very effective.
Russia is bigger than Pluto. (Surface area of Pluto: 16.7x10^6 km^2; Surface area of Russia: 17.1x10^6 km^2)
If you melted down the Eiffel Tower, the pool of iron would be less than 3 inches deep (in a square area the same dimensions as the tower base).
John Tyler, who became president in 1841, has 2 living grandchildren.
Mammoths were alive when the Great Pyramid was being built.
If an atom was the size of our solar system, a neutrino would be the size of a golfball, to scale.
Humans share 50% of their DNA with... bananas.