Arlington National Cemetery is a real time commitment — fit it in only if it's a priority.
Allow 2–3 hrs.
The Changing of the Guard at the Tomb of the Unknown Soldier is genuinely solemn and unforgettable, and the hilltop views back over DC are superb. The catch: it's across the river in Virginia, the grounds are large and steep, and as an active cemetery it asks for a quiet, respectful pace — not a rush.