Tourists can now experience life on Mars – in a cave in northern Spain.
At Astroland's "Ares Station", a replica of a human colony on the red planet, participants carry out "spacewalks", simulate weightlessness and learn how to grow food in specialised laboratories.
Organisers say the lack of atmosphere, extreme low temperatures and presence of cosmic rays on Mars would mean new societies would likely be forged below ground.
Visitors complete 26 days of online courses and undergo three days of intensive training before entering the 1.5 km, 60 metre-high cave near Arredondo in Cantabria. They stay for three nights and pay €6,000 each for the privilege.
Astroland said that "Ares Station" has seen one successful mission already and is now open to explorers wanting to get a taste of Martian life.