Case file · High strangeness
'Slow Down', the falling tone
On 19 May 1997 US hydrophones in the Pacific recorded a sound that slowly fell in pitch for about seven minutes, which researchers named 'Slow Down'.
1997 CE · -63.00, -59.00 · status: explained
The account
It was heard on several hydrophones thousands of kilometres apart, and was placed in the Southern Ocean off the Antarctic Peninsula. Position approximate.
The sceptical view
NOAA's leading explanation is a large iceberg grinding along the seabed as it drifted.