CastleGate

CastleGates is a plugin (source) which allows for redstone-activated retractible vertical gates.

Creation
First, identify two blocks which will serve as your gear blocks. These are the blocks which will retract or show any blocks between them on activation. Left click the first block with a gold ingot to turn it into a gear block. This will consume the gold ingot. Left click the second block with another gold ingot to turn it into a gear block and create a link with the first gear block.

Now you can put whatever blocks you want between the two gear blocks. When a redstone signal is sent to one of the gear blocks, the blocks between the two gear blocks are hidden or shown, depending on the previous state.

Wiki
More information can be found here: https://github.com/DevotedMC/CastleGates/wiki