Where: 19 Smithsonian Institute museums around Capitol Hill
Earn your stamp: Hunt down such artifacts as the only portrait Elvis ever sat for, at the National Portrait Gallery in the Smithsonian, the world’s largest museum complex. Download the Visitor’s Guide app (put out by Smithsonian Magazine) to create your own scavenger hunt based on your interests and time.
When to go: Now, before the spring break and summer vacation crowds start piling into the Nation’s Capital.
Plan it now: Free museum admission (si.edu). Download the app for 99 cents at smithsonianmag.com