For Rio de Janeiro native Marcio Mizael Matolias, home is a sandcastle that he built on the beach. He has lived there full-time for the past 22 years. The fantastical appearance of the three-square-meter castle was inspired by architects Antoni Gaudi and Oscar Niemeyer. It also houses a used bookshop that he runs to fund his living expenses. In Rio, the average monthly rent is almost double residents’ average pay. It makes Matolias’ rent-free abode an attractive option.