A look at how residents of Tokyo use their rooftops in one of the world's most densely populated cities - watch City Rooftops: Tokyo above...

38 million Japanese live together in the most populated urban area in the world. No wonder that the people of Tokyo have taken over the roofs to have extra space. A traditional Japanese garden and tea house, along with a martial arts class, take to the skies in search of tranquility.

Presented via RTÉ's innovative content agreement with ARTE, the European culture TV channel.