One of my favorite spots in D.C. is the Sculpture Garden at the National Gallery of Art. The block-long green space is filled with oversized modern art pieces from the gallery’s permanent collection. You'll see work by artists such as Claes Oldenburg and Joan Miró. A path winds through all the sculptures, and along the way are a few benches where you can relax and people-watch. I guarantee that as soon as you sit down, you’ll forget you’re in the middle of one of the most popular areas of the city. The beautifully landscaped garden also features a small café and pool.
During warmer months, I always advise visitors to come when they want a break from the museums that line the west side of the Mall. From May through August, the garden turns into a wonderful jazz venue every Friday afternoon. In the winter, the garden's water feature is transformed into an ice-skating rink.