Tranquility Base
Apollo 11 · July 1969 · on the Moon, 0.67° N, 23.47° E
Where Neil Armstrong and Buzz Aldrin first walked on the Moon, on the smooth lava plain of the Sea of Tranquility. Near the middle of the Moon's Earth-facing side, so the Earth hangs high in the sky and hardly moves: over a month it only wobbles a few degrees while going through its phases.
What is there
Apollo 11 descent stage (Lunar Module, NASA)
The bottom half of the Apollo 11 Lunar Module, still standing where it landed: it served as the launch pad for the top half, which carried the crew back up to the Command Module in orbit.
Apollo 11 flag (Flag, NASA)
Planted a few metres from the Lunar Module, it was blown over by the ascent engine's exhaust at lift-off — Buzz Aldrin saw it fall. After 50 years of unfiltered sunlight its colours have almost certainly bleached white.
Apollo 11 early seismometer (Experiment, NASA)
Apollo 11's solar-powered seismometer, set up in a few minutes on the first moonwalk. It recorded the astronauts' footsteps and the Lunar Module's lift-off, then moonquakes for three weeks until it overheated in the lunar noon.
Apollo 11 laser retroreflector (Experiment, NASA)
100 corner-cube prisms that send light straight back where it came from. Observatories on Earth still fire lasers at it today and time the echo: the Moon's distance to a few millimetres — it is moving away from us 3.8 cm a year.
Stand at Tranquility Base in Stellingo: the ground is shaped from orbiter elevation maps and photos, the hardware is placed where it really is, and the sky above — the Sun, the Earth, the stars — is the real one, at any date you choose.