Two voids where the towers stood, with the names of every person killed cut through the bronze parapets. The plaza is free. The museum below is not, and it is very hard.
The plaza
Michael Arad and Peter Walker’s design does one thing and does it completely. The footprints of the two towers are left as square voids, each an acre, with water falling thirty feet down all four sides into a second, smaller void at the centre that you cannot see the bottom of. The water noise cancels the traffic, so standing at the parapet the city goes quiet.
The names of the 2,977 people killed on 11 September 2001 and the six killed in the 1993 bombing are cut through the bronze rail, arranged by what the designers called meaningful adjacency — colleagues together, first responders with their units, people who died together placed together, based on requests from the families. On a person’s birthday, staff place a single white rose in their name.
The plaza is free, open every day, and needs no ticket. A great many visitors do only this, and that is a reasonable choice.
The Survivor Tree, a Callery pear pulled out of the rubble as a burnt eight-foot stump and nursed back in a Bronx nursery, stands on the plaza and is now taller than the buildings around its planting bed.
The museum
Underground, in the archaeological space between the original slurry wall and the tower footprints. It is a ticketed, timed-entry museum and it is emotionally severe in a way that is difficult to prepare for.
The route descends past the Last Column — a thirty-six-foot steel beam covered in the messages, photographs and unit patches left by recovery workers, the last piece removed from the site — and the Slurry Wall, the original retaining wall that held the Hudson back and did not fail.
The historical exhibition is a minute-by-minute account of the day, using recordings, voicemails, news footage and objects. There are rooms within it that carry warnings at the entrance, including one containing the recorded voices of people who died. Those rooms can be walked around.
The memorial exhibition, In Memoriam, is a portrait wall of every person killed, with an inner chamber where you can hear a recording about any individual.
Objects include a crushed fire truck, a section of the antenna, the Vesey Street stairs that hundreds used to escape, and personal effects that the families donated.
Practical
Book timed tickets in advance. There is a free-admission window one evening a week with tickets released online ahead of time; it books out immediately.
Two to three hours is normal. There is nowhere inside to sit and recover except a small reflection room, so plan a break afterwards — the plaza itself, or the water.
Children
The museum’s own guidance is that it suits ages ten and up. Younger children will not follow it and may find parts frightening. The plaza is fine at any age.
Above ground, the Oculus transit hall is next door, and One World Observatory is at the north-west corner of the site.
More Museums
The Metropolitan Museum of Art
Two million objects across five thousand years, in a building you cannot see in a day. Pick three departments and accept that you are missing the rest.
Museum of Modern Art
Starry Night, the melting clocks, Les Demoiselles d'Avignon and Warhol's soup cans, in six floors that can genuinely be done in three hours.
American Museum of Natural History
The blue whale, the dinosaurs and the dioramas, in a rambling complex of twenty-odd interconnected buildings on the west side of Central Park.