What's here
The AMNH covers 45 permanent exhibition halls across four floors, with collections in paleontology, anthropology, astronomy, and natural sciences. The building itself is a landmark — a complex of connected structures built between 1869 and the 1930s, with the newer Rose Center for Earth and Space (2000) attached to the west side.
The dinosaur halls
The fourth floor Fossil Halls are the museum's most visited section — and genuinely deserve to be. The mounted dinosaur skeletons here include some of the most complete specimens in any museum worldwide, presented in actively combative poses that reflect current scientific understanding of dinosaur behaviour rather than the static presentations of older museums. Allow at least an hour here.
The Rose Center for Earth and Space
The Hayden Planetarium, housed in a sphere within the Rose Center's glass box, runs regular space shows narrated by prominent scientists. These need a separate timed ticket beyond general admission and are worth booking in advance. The Big Bang theatre in the base of the sphere runs on a continuous loop and is included in general admission.
What to skip on a first visit
The Hall of Ocean Life (ground floor, enormous blue whale) is a rite of passage and worth a brief stop, but the overall exhibit is somewhat dated relative to modern marine science. The North American Mammals and African Mammals halls are visually impressive as diorama work — the painted backgrounds are a genuine art form — but can be walked through quickly if time is short.
Admission and logistics
Like the Met, the AMNH uses a "pay-what-you-wish" suggested admission for New York State residents; standard admission applies for out-of-state and international visitors. The museum is on the Upper West Side at 79th Street, directly across from Central Park — easy to combine with a Central Park visit. Wednesday evenings have extended hours (open until 8pm) and are less crowded than weekend afternoons.