How to explode a hard drive

I know this isn't strictly tech, but I felt it's the best place for it.

People talk (on 4chan and such places) of raids by the police on their house to recover hard drives due to suspicions of CP or of pirated content.
I was wondering if anyone knew of a case where someone actually managed to destroy their Hard Drive, either remotley or before anyone could get to it, or any stories of the sort.
Could it hypothetically be fitted with some sort of... remote water filling thing?
Post anything relevant please.

There's no point in damaging the harddrive physically. Even if the plate is in pieces, they still can read some data from it, it just needs some special technology.

HDDs are magnetic media. All you need is a strong enough magnet and no one would be ever able to get any usable data out of that HDD.