More than thirty blocks of derelict buildings were cleared away in the mid-twentieth century for the Jefferson National Expansion Memorial, dedicated to the US president who negotiated the Louisiana Purchase and thereby opened up the West, as well as to the pioneers who journeyed along the Oregon and Santa Fe trails. The highlight of the expansive greenspace is the gracefully imposing Gateway Arch (tram rides daily: summer 8.20am–9.10pm; rest of year 9.20am–5.10pm; $10; t 1-877/982-1410, w www.gatewayarch.com), one of the nation’s definitive monuments. Designed by Eero Saarinen and completed in 1965, the 630ft-high stainless-steel parabola is a weighted catenary curve, its outline formed by a heavy cable hanging freely from two points. Provided you’re not claustrophobic, it’s fun to take the four-minute tram ride up the hollow, gently curving arch, as tiny, five-seat capsules carry you to a viewing gallery at the top, where you can linger as long as you like – the views of St Louis, the mighty Mississippi and the surrounding tree-studded plains are spectacular. Lengthy waits are a sure thing in the summer, but you can pick up a numbered ticket earlier in the day and come back at an appointed time. Still, you’ll have to wait again for the elevator, so expect an hour round-trip.