A new world record has been set for the longest echo in a man-made structure. The sound in question was recorded in an underground fuel depot constructed in Scotland before World War Two.

Professor Trevor Cox from Salford University recorded a shot fired from a pistol loaded with blanks inside the Inchindown tunnels near Invergordon.

The previous record was set in 1970, and that echo lasted for 15 seconds.

The new world record set by Cox saw an echo that lasted for a whole 112 seconds. Prof Cox said he was astounded by the results:

Never before had I heard such a rush of echoes and reverberation. My initial reaction was disbelief. The reverberation times were just too long.

We have a clip of the original echo below. Click to have a listen.

And here it is in reverse.

[Source : BBC, The Independent]