The museum below the arch is modern, detailed, and...

The museum below the arch is modern, detailed, and interesting detailing the founding of St. Louis, the American migration westward, and the construction of the Arch. There is a 30 minute movie for $7, a small cafe, as well as riverboat tours and a trip up to the top of the arch. The gift store is one of the best national park stores I've seen. Be warned that you do have to go through a security checkpoint almost on par with the TSA.