Clearly destined for the cinema screen, Tadhg O'Sullivan's documentary, The Great Wall, travels along Europe's borders at a time when the refugee and migrant crisis is intensifying. The documentary highlights the entry barriers to the European Union in the form of wire, concrete and electronic surveillance. The film's narration is adapted from Franz Kafka's short story "The Building of the Great Wall of China."  The trailer is haunting and is down on my list as a must watch for the summer.