Near Montréal's Botanical Garden and next to the Olympic Stadium, you'll discover the engrossing Biodôme, possibly the only institution of its kind. Originally built as the velodrome for the 1976 Olympics, it has been refitted to house replications of four distinct ecosystems -- a Laurentian forest, the St. Lawrence marine system, a tropical rainforest, and a polar environment -- that visitors can walk through and explore. All the ecosystems are complete with appropriate temperatures, flora, fauna, and changing seasons, and all four re-creations are allowed a measure of freedom to grow and shift, so the exhibits are never static (for example, fall in the Laurentian forest sees the changing colors of the foliage). With more than 6,000 creatures of 210 species and 4,000 trees and plants, the Biodôme incorporates exhibits gathered from the old aquarium and the modest zoos at the Angrignon and LaFontaine parks. Among the fauna are specimens of certain threatened and endangered species, including macaws, marmosets, and tamarins. The Polar World contains puffins and four kinds of penguins, from both Poles. Biodôme also has a game room for kids called Naturalia, a shop, a restaurant, and a cafeteria.