They were explored in 1829 by Philippe-Charles Schmerling, who discovered, in the lower cave, the remains of two individuals, one of which, now known as Engis 2, was a fossil of the first Neanderthal ever found; the other was a Neolithic homo sapiens.

A third cave was destroyed because of work on the adjacent quarry, the Ancienne Carrière des Awirs.

[6] A monument for Schmerling, consisting of a bust on a base made of stone, was erected at the foot of the hill in 1989; it was moved to the town square of Awirs in 2001.

[4] The measurements of the upper cave, which opens to the north, are 5m wide, 6m high, 17m deep,[clarification needed] with a small gallery on the right.

Another gallery ascended into a second, smaller, chamber which was strewn with bones:[7] There was a third cave, to the east, which was destroyed in the exploitation of the quarry.