The steaming Conundrum Hot Springs, west of Castle Peak (14,265ft), are the reward for 8.5 miles of tough climbing on the Conundrum Creek Trail (USFS Trail 1981). As it's hugely popular, the Forest Service is drafting new visitation guidelines (including a possible permit system) following a sharp uptick in visitation, which has essentially resulted in the area getting completely trashed.

The several pools here have outrageous alpine views, including glimpses of steep avalanche chutes and waterfalls, and are certainly a worthy destination (although it's now more of a party spot than a rejuvenating one). Be sure to check in with the ranger office before planning an overnight trip here.