Yes, you can always take your out-of-towners to the top of the Arch, but how predictable is that? How many times can you hunker down in a Kubrickian white bubble car and inch to the top? How about a walk among the roses instead? The Missouri Botanical Garden is world-class, considered one of the most prominent and respected gardens in the world, alongside London's Kew Gardens and the New York Botanic Gardens. It's also a world leader in botanic research; its botanists and biologists scour the rainforests for endangered species and magical new drugs. Like the Arch, we often take it for granted, but that shouldn't diminish its glory: With its variety of gardens, seasonal plantings, gardening hotline (314-577-5143, 9 a.m.-noon Monday-Friday), ethnic festivals and various events, the park blossoms daily in the heart of South City.