...about 5.6m years ago, an extraordinary thing happened: the entire Mediterranean sea dried out for some time. This event left a clear signature in the sediments of the surrounding areas. The sediments that contain the footprints suggest they probably date to the period immediately before this, at about 5.7m years.IOW, this guy got there by boat? :^)
The Med has completely dried out (at least) 40 times, the last time was five million years ago. These guys may have walked there.
There is a 2 mile thick salt layer on the bottom of the Med with the sort of salt crystals that forms only when exposed to direct sunlight.