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Photo: via Wikimedia Commons, CC BY-SA 3.0
A large park with plenty of big lawns, wooded areas, and a few ponds. The park and the nearby parking garage are closed for renovation; however, the arch remains open.
Gateway Arch National Park is a national park of the United States located in St. Louis, Missouri, near the starting point of the Lewis and Clark Expedition.
© OpenStreetMap contributors
Designed by Eero Saarinen and built in 1965, this is the world's tallest national monument, built to be a symbolic gateway to the West. The icon of the city, the Arch is right on the bank of the Mississippi and offers an inspiring sight to travelers coming in from Illinois. There's a gift shop and a confectionery, as well as an inspiring film called "Monument to the Dream," about the building of the Arch; it is an exceptionally well-made and memorable tribute to how a vision was made tangible. But the main attraction is the Journey to the Top; you'll ride a unique tram/elevator—essentially a cross between a cable railway and a Ferris wheel—up either the north or south leg to the top of the arch, where you can see for dozens of miles into Illinois and Missouri. The cars are very small; they hold five very close friends or relatives each, and are not suitable for the claustrophobic. Tickets sell out during peak season; expect a long wait on major summer holidays to go to the top.
Basilica of Saint Louis, King of France
The first cathedral built west of the Mississippi River (1834), this is the only building that was spared when the park was constructed. It's still an active Roman Catholic basilica.
Take a cruise down the Mississippi River on the Tom Sawyer riverboat. The boat has paddle-wheels (for display only) and a narrator with guide you around the industrial buildings on the Mississippi waterfront. They also offer cruises with dinner and live music at certain times and also a day trip to historic Kimmswick, Missouri.
The site of the historic Dred Scott slavery case which was one of the seeds of the Civil War. While the Park is under construction, you can buy tickets to the arch here. The Courthouse also holds exhibits from the now-closed Museum of Westward Expansion, which used to be underneath the Arch.
Just north of the Arch and part of Downtown St Louis, and the second oldest neighborhood after Soulard, "the Landing" is what amounts to St. Louis' old town. You are likely to enjoy the cobblestone streets and the shops, restaurants, bars, nightclubs, and a bizarre wax museum. Next to the Landing is a $400 million casino complex called Lumiere Place, featuring a Four Seasons hotel, nightclubs, 75,000 square feet of casino gaming, and an innovative multi-colored light feature spanning 24 vertical floors on the exterior of the building that lights up St. Louis' skyline. Not many original buildings on the Landing remain, as the area is constantly undergoing new developments and rehabilatation of older buildings. Nightly horse-drawn carriage rides take you around the Landing and much of Downtown.
MLB
St. Louis' Major League Baseball team (and the 2011 World Series champions) has won 11 World Series titles, the most of any National League team, and second only to the New York Yankees. The Cardinals play in the Central Division of the National League. Behind-the-scenes tours of the ballpark are available daily all year (except for days with an afternoon home game) at 11AM and 12:30PM.