Necessity is the mother of all invention, and nowhere is that truer than at Arapahoe County's South Platte River Run Park. When the cities of Littleton, Englewood and Sheridan needed flood mitigation and drainage-fixing, they dreamed up the $15 million park, a mile stretch of outdoor fun along the Platte in Arapahoe County that will solve their water woes — and treats residents to splash-tastic fun. Although the entire park won't be finished until 2018, one of its more unique amenities opened last year: man-made waves on the Platte for surfers. The finished park will include a playground and protected habitat for wildlife, so you can hang ten in a totally environmentally chill way, brah.