No only child has been a U.S. President.
Vermont is the only New England state without a seacoast.
At birth a human has 350 bones, but only 206 bones when full grown.
The only bird who can see the color blue is the owl.
The Basenji is the only type of dog that does not bark.
The only one-syllabled U.S. state is Maine.
A rainbow can only be seen in the morning or late afternoon.
Theodore Roosevelt was the only president who was blind in one eye.
Panama is the only place in the world where you can see the sun rise on the Pacific and set on the Atlantic.
Texas is the only state that permits residents to cast absentee ballots from space.