I haven't told anyone about this before.
I once built an illegal Large Hadron Collider, but unfortunately not quite to specification, which caused the end of the world by creating a black hole singularity
<my bad> - luckily, an unforeseen side-effect of the quantum decoherence was to transport me to a parallel world in the multiverse, so I survived.
I am sure I will get it right this time - wish me luck!