Want a base nobody can find? Build it underwater! This guide shows how to make a glass dome base on the ocean floor with glowstone lights inside. It takes a little planning (you'll need to keep the water out), but it's one of the coolest bases you can build.
Glass Blocks
~64
Glowstone
~16
Doors
2
Sponges
~8
Ladders
~8
Wood Planks
~16

Find a shallow spot of ocean. Place a door at the seafloor to make an air pocket, then build a hollow glass dome around it. Use sponges to soak up water inside the dome so you can breathe.

Make a doorway with two doors and a ladder shaft going up to the surface — this acts as an airlock so water stays out. Line the entrance with planks so it's easy to spot from outside.

Place glowstone around the dome so it glows through the glass and looks amazing at night. Add your bed, chests, and crafting table inside. You now have a secret underwater lair!
★ Pro tip: Always keep a door or trapdoor between you and the water — if a block breaks, the airlock stops your whole base from flooding.