The Prince of Wales laid a wreath at Washington's World War II memorial on the royal couple's final day in the city.
A trumpet sounded as Prince Charles and the Duchess of Cornwall viewed the memorial, which stands between the Lincoln Memorial and Washington Monument.
Prince Charles and Camilla chatted to veterans. After hearing one ex-soldier's story, the duchess said: "That's so amazing, fantastic, it's so very nice of you to come today, I'm thrilled."
The royal couple also visited the US capital's Folger Shakespeare Library to watch part of a children's performance of Much Ado About Nothing.
The prince and the duchess got on the stage and were shown around the theatre and the world's largest Shakespeare collection, before leaving for New Orleans.
Prince Charles and Camilla climbed a levee in New Orleans to view the destruction caused by Hurricane Katrina.
About 80% of New Orleans was left underwater after the hurricane, which killed some 1,200 people.
The royal couple met emergency workers and the Jones family, who lost their home in the hurricane and are in temporary accommodation on a cruise ship.
Charles and Camilla flew from New Orleans to San Francisco, where they will visit a farmers' market later on Saturday.