My experience of what jail is like is taken from the 12 hours I spent under arrest in May of 2001 at the Long Beach city jail, although I've also been in what used to be the jail in West LA, where the domestic abuse team now has its office. This is not a description of what prison is like; I do not know what prison is like.
Jail is not like what you see on television or in film. Jail is less photogenic, dirtier, more cramped, more primitive, and more institutional.
The cell block I was on was made up of a long hallway or common area with the two person cells on one side. The common area is behind bars, with two doors leading into it. Between the first and second doors are controls for the individual cell doors. In the common area, there are phones, and outside the bars a television is visible. There is no external light, and there are no clocks. There are picnic tables set up, institutional things in gunmetal grey and cement, bolted to the floor. The phones are similarly indestructible, ancient black plastic things with very short metal cords, lousy sound quality even when other prisoners are being quiet. You can make all the calls you want if you're not in lockdown, but all of them will be collect calls with a little introductory message saying the call is from an inmate at the Long Beach city jail. When you're in lockdown, you can't make phone calls. If you didn't get one earlier, that's too bad.
The two person cells are just long enough for the beds, metal shelves set up one over the other, with foam mattresses covered in thick institutional plastic that reminded me somehow of gym class in grade school. The plastic is easy to clean, but has a slightly rough texture that makes it so you can't really tell when the last time it was cleaned was. The plastic sticks to skin, although fortunately it's too firm to stick hard. There are no pillows. Each prisoner is given a blanket when they come in. The blankets come from a pile in the hallway. They're thick grey things, vaguely military in appearance. Again, it's impossible to tell how clean they are, but my impression is that they're not very clean. They're kept on a floor that doesn't appear to be all that clean, and when I was bailed out, I was told to fold my blanket and leave it where I found it, back on the floor, presumably for the next person to use. They had me flip the mattress half-over, too, a position that suggests it may be clean. The space between the bottom bunk and the top bunk is enough to sit up in. The bunk is wide enough for one person to sleep on, provided they do not toss and turn. The beds are cot-sized or smaller. There is no ladder up to the top bunk, so possible steps up include the bars, the bottom bunk, and the toilet.
The room is wide enough for the bunks and toilet, with enough room between the toilet and the bed that they're not right up against each other. The toilet is an indestructible utilitarian design I've never seen anywhere else, a kind of beige metal that doesn't curve much on the bottom, descending straight into the floor instead. The sink is built into the back of the toilet, where the tank typically is, forcing you to lean over the toilet if you want to use the sink. The toilets smelled vaguely of cleanser that hadn't caught up with dirt, of dirty public bathrooms, and a smell that I can only describe as the smell of jail. Toilet paper was on the sink or on the floor, which was also dirty. The whole room is incredibly close, to the point where even before lockdown was declared, no one wanted to go into these rooms even for the minute it takes to piss.
The bars across the front of the cell are metal, a dark dull color, rods set a few inches apart with horizontal crosspieces about every foot. The door is in front of the toilet, wired to move on a track. The movement is noisy, disconcerting.
Outside the larger cell block are other rooms for holding. These rooms are slightly larger, but also terribly close. They have benches running around them at calf height with spaces in front of the door and around the toilet, which is in a corner. Various of the toilets are broken, and none of them have lids, so they just stink. The door here is solid with a flap in the middle of it. The room is grey and the lighting is terrible. The benches are stained. I believe there was a drain in the floor.
Outside here there was a sink set into a recess in the wall. This was the sink I was sent to to wash of the finger printing ink. There was powdered soap in a plastic container. There is no soap in the cells.
The entire setup is claustrophobic and disempowering. Everything is in institutional colors that would give the impression of being dirty even if they weren't. The colors are depressing, with brown and grey predominating. The air is heavily recycled, although warm. There is no exterior light, no way to tell where you are or what time it is other than the jailers' say-so. You eat when they say, you sleep when they say, you go into lockdown at their discretion. Although they can't see you from the desk, they can hear you. There is no privacy in the cage, and it's impossible to forget that you're in one.