[tomhazledine]

Such an effective trick when you experience it in person.

I remember visiting Goonhilly Earth Station as a boy (a collection of huge satellite dishes at the very tip of Cornwall, UK) and they had two small (~2 or 3m diameter) dishes facing each other on either side of the visitor centre. Completely blew my mind to hear someone whispering from all the way across the room!

[dylan604]

Any building with a domed ceiling is ripe for interesting reflections as well. There's a story of US congress/senator during a negotiation offering to step to the other side of the room to allow his "colleagues" to confer in private knowingly as he could hear their conversations due to the reflections off the dome.

[euroderf]

Sure. If you take the tour, a guide demonstrates it. Or at least did in the 80s.

[tomcam]

Instant 70s-style album cover