Buying a Washington D.C. Sightseeing Pass is a good way to see more of the USA's capital. The FLEX Pass lets you pick two, three or four tours, tickets or entry fees to a selection of attractions, over a period of 30 days (from pass activation at the first attraction). With the DAY Pass, you can visit as many attractions as you wish on one, two or three consecutive days. Many attractions such as the numerous Smithsonian Museums are free but the Sightseeing Pass includes plenty of cool things to do and see. Visit the International Spy Museum, see famous monuments on a water taxi ride along the Potomac River, head to Madame Tussauds Washington D.C. or browse the landmarks on a self-guided bike tour. There's also a one day hop-on hop-off bus tour included.