Considered one of the leading botany centers of the world, the 250-acre New York Botanical Garden built around the gorge of the Bronx River is one of the best reasons to make a trip to the Bronx. Outdoor plant collections include the Peggy Rockefeller Rose Garden, with 2,700 bushes of more than 250 varieties, the spectacular Rock Garden, with plants from all seven continents and the Everett Children's Adventure Garden, a 12-acre, indoor-outdoor museum with a boulder maze, giant animal topiaries, and a plant discovery center.