In this blog I will be describing how this simple trap works.

Items required:

x1 pressureplate
x1 sand
x1 TnT

First of all dig a deep hole enough for the drop to kill someone.
Secondly place a tnt 2 blocks below surface at the top of your trap.
Lastly place a block of sand on top of the tnt, then put the pressure plate on top of the sand.

How it works: someone steps on the pressure plate which ignites the tnt, which in turn drops to the floor and since the tnt isn't there to support the sand the sand drops also.

This trap is best used on narrow passages to increase the effectiveness consider adding blocks that slow a person such as a web, may also help prevent raids but it all depends on how well you make it.