one of the premiere botanical gardens in the united states, the new york botanical garden in the bronx was modeled after the royal botanic gardens in london. with 48 different gardens and plant collections, nature enthusiasts can easily spend a day admiring the serene cascade waterfall, wetlands, a 50-acre (200,000 m²) tract of old-growth oaks, american beeches, cherry, birch, tulip and white ash trees — some more than two centuries old. garden highlights include an 1890s-vintage, wrought-iron framed, "crystal-palace style" greenhouse; the peggy rockefeller memorial rose garden (originally laid out by beatrix farrand in 1916); a japanese rock garden; a 37-acre (150,000 m²) conifer collection, extensive research facilities including a propagation center, 50,000-volume library, and a herbarium archive of hundreds of thousands of botanical specimens dating back more than a century. at the heart of the garden are 40 acres (162,000 m²) of virgin woodlands which represent the last stretch of the original forest which covered all of new york city before the arrival of european settlers in the 17th century. the forest itself is split by the bronx river and includes a riverine canyon and rapids, and along its shores sits the landmark lorillard snuff-grinding mill dating back to the 1840s.