Take a walk around the National Mall! Visit the Washington Monument, the Lincoln Memorial, the Jefferson Memorial, or the George Mason Memorial (where we got engaged!). Parking might be difficult so we suggest taking an Uber.
Go shopping on M Street, get lunch, or compare the rivaling cupcake shops -- Baked & Wired or Georgetown Cupcakes. Hint: Baked & Wired is better...
Take pictures on either (or both) sides of the Capitol, the place where we could have met but didn't!