How to build a hidden lava entrance

Always looking for ways to hide my cake, I have built a new secret entrance, and I will share it with you. As long as you stay away from my cake! The secret entrance is well hidden and probably not going to be found, who's foolish enough to jump into a stream of lava!?

Nothing suspicious about this...

Create a hidden passage underneath stairs.

There are a lot of secret passages and entrances you can make in Minecraft using pistons, here I will tell you how to create a hidden entrance underneath a stairway. Like the image below.