I was messing around with boats, when I came across the fact that you can easily travel through bedrock (or any block for that matter) using a simple glitch.
Steps to recreate:
1. Use /summon Boat ~ ~ ~ {Passengers:[{id:"Boat"}]} to summon a double boat tower on top of the block you want to travel through
2. Break the top boat, and quickly jump in.
Of course you can travel through bedrock if you have access to commands.