By popular request, this is a variation of a previous visualization I did. Below is a visualization of the lifespan of every US president. In 1822, every single one of the first 19 US presidents was alive except for George Washington. Since then we've had a few other periods of 18 past, present, or future presidents being alive, though never more than that. Some more fun facts:

Eight future US presidents were alive during the signing of the Declaration of Independence in 1776

Martin van Buren was alive during the US Revolutionary War. Woodrow Wilson was president during World War I. Their lives overlapped during the US Civil War.

Ronald Reagan and Theodore Roosevelt both lived during World War I