Most powerful bomb ever constructed

I normally have zero interest in weaponry, but Damn Interesting's story about the most powerful bomb ever constructed actually caught my attention today. It talks about the 1961 detonation of a Soviet device code-named "Ivan". The article's conclusion is interesting:

Even at half strength, Ivan was so powerful that it was completely impractical. Much of the explosion's energy radiated upwards into space, and that which didn't was so excessive that using the device on any populated targets world would have resulted in adverse effects on Russian interests. It served as nothing more than a show of force, and in that respect, it served its purpose well. Thankfully, no other weapon with the massive destructive power of Tsar Bomba has ever been built.

(Via Digg)