Elevators are methods of vertical travel, going either directly up or down. In civ servers, the most prevalent type of elevator is the gold block elevator, though minecart elevators are also used.
Gold Block Elevators
With this plugin active, all gold blocks (under certain conditions; see below) are turned into elevators. While standing on a gold block, you can left click or press shift to go down, and right click or press spacebar to go up, the exact controls will depend on which civ server you are on, some servers this can be changed within the /config command. Your "destination" must be another gold block which is in-line vertically with your current gold block. CivRealms 2.0 was the first server to introduce the gold block as an elevator.
Many consecutive gold blocks may be chained vertically to create "floors". Right click or jump multiple times to go up multiple floors, and similarly for going down multiple floors.
To be considered a valid elevator, a gold block must have at least 2 blocks of air above it. Signs, fence gates, or other non-solid blocks will not work, the 2 blocks must be pure air. It does not matter if the gold blocks are reinforced, and you cannot "lock" an elevator by putting it on a certain namelayer group.
Though slightly cruder, minecarts (and also boats) can also be used to create elevators. If there is not enough room to stand when exiting a minecart or boat, the game will teleport you up to the highest available spot possible.
Upon exiting a minecart, starting from the sky height, the server will check for a block with 4 blocks of air above it. If no such block exists in the vertical column containing the minecart, the player will instead be killed instantly. This can make it dangerous to use minecart elevators blindly, as they could be a trap.