"It is a cliche to call Gaza an open-air prison, but to many people it feels not only as if there is no way out, but also that the walls are closing in. Gaza is just 24 miles long on the coastline — less than the length of a marathon. At its narrowest it is just four miles, an hour’s walk. The enclave is surrounded by Israeli perimeter fence, bristling with cameras, watch towers and remote-controlled machine guns. On the Egyptian border, once honeycombed with Hamas smuggling tunnels, there is now a broad buffer zone, scraped clean by bulldozers, as forbidding as a no man’s land. And the sea? Gaza fishermen are blocked by Israeli gunboats and forbidden to venture beyond six miles. For young people, the sea that once brought relief is now so polluted by untreated human waste that the Health Ministry has warned bathers to stay away."