CARLSBAD, N.M. (AP) — Carlsbad Caverns is celebrating the highest number of visitor in 15 years. The national park says it saw higher-than-average visitation for the 2017 spring break season, hosting over 42,000 people in the first three weeks of March. That's a 44 percent increase in visitors compared to the same period in 2016. The park is known for its underground limestone caves.