We didn't need to read Sunset magazine to recognize that Denver has the country's best riverfront. But a visit to the South Platte River wasn't always a day at the beach. Over a century ago, it was "a miserable yellow melancholy stream," according to Mark Twain. "I wouldn't leave it out at night. Some dog might come along and lap it all up." And three decades ago, before the Platte River Greenway Foundation started cleaning up the riverfront, the stretch of the South Platte running through metro Denver was a noxious mess. Today, though, miles of walking/biking/running paths course along its pristine banks, leading you on an urban adventure under viaducts, past arenas and ballfields, and right into the heart of the Central Platte Valley. There, the Platte now anchors a stretch of parks ranging from the Denver Skatepark on the north end to Bee Hive Park on the south, near the new stadium. And thanks to some new public art, we even have a ship's mast reaching out of the valley toward downtown.