A possible concise summary is:
A group of urban explorers from Ukraine visit a secret bunker in Budapest, Hungary, that was built for the communist party in the 1950s. They enter the bunker through a well-house and a shaft, and find various rooms, equipment, and documents from the Soviet era. They also access the metro tunnel, where they encounter some workers and locomotives. They have to wait until the night shift is over before they can explore the metro further. They film their adventure and comment on their findings, making jokes and references to history and politics.
Here are the key facts extracted from the text:
1. The text is a transcript of a video where a group of explorers visit a secret bunker in Budapest, Hungary.
2. The bunker was built in 1953 for the members of the Hungarian communist party and the parliament, in case of a nuclear attack or air raid.
3. The bunker is connected to the metro system, which has a hermetic door that can block the tunnel from explosion, water or radiation.
4. The bunker has a ventilation system, a diesel generator, an elevator and a water reservoir.
5. The explorers have to avoid being detected by the workers or the security cameras in the metro.
6. The explorers wear hoodies from their own shop and joke about Stalin and hip-hop.