SOSUS and its reuse for whale acoustics, including the 52 Hz call

evidence

SOSUS was installed by the US Navy from the mid-1950s as a network of seafloor hydrophone arrays across the Atlantic and Pacific, exploiting the deep sound channel so that low-frequency sound travels great distances; its mission was declassified in 1991. The 52 Hz call was first identified in 1989 by William Watkins of the Woods Hole Oceanographic Institution from Navy hydrophone data, and the same call was tracked seasonally across the North Pacific over hundreds to thousands of kilometres between recordings. V55 verification basis: retrieved in search summary; neither the Watkins publication nor a Navy declassification record was consulted.

A evidence is not a place. Drawing it on a map would assert something about the world that no stored fact supports.