Occurred on August 3, 2021 / Cabo de gata, Spain
Info from Licensor: That video is from the summer. Me and a friend of mine Pau Farrero from Girona, Spain (my hometown) were on vacation with his parents to the south of Spain, in Cabo de Gata. We came across these underwater tunnels while snorkeling, and decided to explore them. We both have experience in freediving and can hold our breath for around 2 minutes, so we were fine. I have many more videos exploring different tunnels too.