Timpanogos Cave National Monument is one of the best cave systems open to the public in Utah — a complex of three connected caves inside the flanks of Mount Timpanogos, reached by a steep 1.5-mile trail rising 1,100 feet from the canyon floor. The caves contain an impressive range of speleothems: stalactites, stalagmites, helictites growing in every direction, and the rare "cave coral" formations found along the walls.
Guided tours run from May through October; tickets must be purchased in advance and sell out early in the season. The trail up to the cave entrance is itself a worthwhile hike with canyon views. Budget two to three hours for the full experience.