(202) 633-1000, www.nasm.si.edu
Visitors annually: 9 million
View Buzz Aldrin’s space suit, climb into a flight simulator, and examine a lunar rock at this museum, where you’ll find the world’s largest collection of historic aircraft and spacecraft, along with artifacts as big as rockets and as small as microchips.

HALEY SHAPLEY is a writer based in Fort Worth, Texas. Her favorite tourist attractions are Cedar Point in Sandusky, Ohio, and the Franklin Delano Roosevelt Memorial in Washington, D.C.