Sure, triathlons are challenging and fun. But the run-bike-swim routine can get old. Add a little adventure to your multi-sport race schedule by adding climbing, kayaking, cross-country skiing, orienteering, or mountain biking to the mix. The best part about these races — still niche, but growing in popularity — are that they tend to be in locations with mountains, trails, and water. In other words, the kind of locale you might seek out for any sort of adventure. Here are eight multi-sport races that will push you to the limit.