The banya is a fixture of every home in Siberia. Apartment dwellers do not have the luxury but then, don't need it in the same sense. The banya serves as sauna and bathroom for homes that do not have plumbing. Bathroom as in bathing and washing, not to be confused with the toilet which is out back.
The banya is always in a separate building from the main house, at least partly for fire safety reasons. Luda and Valerie's banya is just across from their house. The first door was Luda's kitchen until they got plumbing and she moved it into the house, the old kitchen now serving as summer kitchen and store room. The second door is to the banya. Theirs is a simple two room banya with a small entry room for dressing and for servicing the firebox (bottom) and the water reservoir (top) which you can see in the picture below. The green paint is over brick or concrete.

The fire in the banya was kept going almost all the time as the reservoir served as a source of hot water for washing clothes and dishes. In winter, one made a quick dash across a cold yard, to a warm banya for morning washing up and teeth brushing, etc. When it was time for a bath or sauna and bath, the fire was revved up to heat the water, the room and the rocks as hot as you wanted to stand. In the picture below (which is the back side of the picture above) you can see the construction of Valerie's system. There is a pipe running from the fire box under the rocks to and through the brick chimney at the back. The rocks get hot. You dip water from the reservoir and throw it on the rocks where it explodes in a cloud of steam. Beside where I was standing to take the picture is a wooden bench to sit or lie on while you steam yourself.

The wooden barrel is for cold water. Once you are steamed as much as your lungs can stand (and it is a learned process) you take hot water from the reservoir and cool it from the barrel and give yourself a bath, ending with a cold water rinse. The floor is wooden slats with good gravel drainage under it so splashing water around is not an issue, in fact it is expected.
The banya is wonderful. You feel cleaner than just a shower but it is not as quick or as handy. And it is NOT a place for unattended children or clumsy adults.
It certainly is part of Russian tradition though -идти в банё (ydti v banyo - go to the banya) is a polite way of telling someone to go to hell.