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Public displays

The great fossil collections that are open to public view occupy the entire fourth floor of the museum. The fourth floor exhibits are accessed by the Miriam and Ira D. Wallach Orientation Center, which opened in 1996. On the 77th Street side of the museum the visitor begins in the Orientation Center and follows a carefully marked path, which takes the visitor along an evolutionary tree of life. As the tree "branches" the visitor is presented with the familial relationships among vertebrates, called cladograms. A video projection on the museum's fourth floor introduces visitors to the concept of the cladogram.

Many of the fossils on display represent unique and historic pieces that were collected during the museum's golden era of worldwide expeditions (1880s–1930s). On a smaller scale, expeditions continue into the present and have resulted in additions to the collections from Vietnam, Madagascar, South America, and central and eastern Africa.