Il buco (2021) on Netflix

Plot summary

During Italy's economic boom, Europe's tallest building rises in the prosperous north while a group of young speleologists from Piedmont heads south. Having explored the caves of northern Italy, they travel in August 1961 to the Calabrian plateau in the Pollino, where local shepherds point them to the entrance of the Bifurto Abyss. The cave drops almost 700 meters into the earth, and an earlier expedition turned back at 440 meters, so the group has no maps for the descent. In a nearby village the arrival goes largely unnoticed, and news reaches the town through a television in the square. On the plateau, an old shepherd, the only witness to the untouched territory, watches the intruders.