Why has nobody on Earth seen Tsiolkovskiy?
Because the Moon is tidally locked: it turns once on its axis for every orbit it makes, so the same hemisphere always faces us. Tsiolkovskiy sits at 20.4° south, 129.1° east — well onto the far side. It was first seen by the Soviet probe Luna 3 in 1959, and no human eye has ever looked at it from the ground.
Why is the floor dark?
It is filled with mare basalt — the same dark volcanic rock that makes the large gray patches on the nearside. That is common where you are looking now and rare where Tsiolkovskiy is: the crust is thicker on the farside, so only an impact big enough to punch deep into it can let basalt reach the surface. Tsiolkovskiy is one of only a few farside mare deposits.
What does Tsiolkovskiy look like as a 3D print?
It gives you the biggest contrast of any destination here: a flat, smooth basin floor with a 3,400-meter mountain standing in the middle of it, ringed by terraced walls. Because the floor is genuinely flat, the peak has nothing competing with it, and it prints as a single clear landmark rather than a field of texture.
At 185 kilometers across it is also the largest feature of the four, so a selection that fits the whole crater covers a lot of ground per millimeter of print.
What is OrbitStudio?
OrbitStudio turns real NASA lunar elevation data into 3D-printable models. You pick a region of the Moon on a globe or a flat map, choose a jigsaw puzzle or a solid ornament, and get one ready-to-print file with terrain and borders already separated and colored. No CAD, no mesh repair. The farside is covered as completely as the nearside, because the elevation data comes from an orbiter rather than from a telescope.
Trying it is free and needs no account: pick a region, generate it and turn it around in 3D. Downloading the model — STL files and pre-colored 3MF files for Bambu Studio or OrcaSlicer — uses one credit from a pass. The generator covers Mars too.
Other landmarks
The night sky, too
OrbitStudio Sky, the night-sky tool, turns the sky over any place, on any date from 1900 to 2100, into a 3D-printable star map. Its STL is free.