Fishing might not be the first thing that comes to mind when Denverites think of the South Platte River. Pollution, maybe. Or used condoms. But the river that winds through the Mile High City is more than most people give it credit for, especially when it comes to stalking big-ass fish. In recent years, fly-fishing the South Platte for carp has become increasingly popular; there's even an annual Carp Slam fly-fishing tournament hosted by the Denver chapter of Trout Unlimited. Carp are resilient freshwater fish that can grow to nearly 100 pounds, and they're plentiful in the South Platte. That doesn't mean they're easy to catch, though: They're excellent at avoiding fishermen's hooks, which makes reeling one in that much more of an accomplishment.