A construction boom in the run-up to the 2020 Tokyo Olympics is changing the face of Japan's capital. The unsung heroes of this transformation are the skyscraper construction workers who ply their trades at the top floors of these towering buildings. Many young people seeking opportunity flock to Tokyo to work at these dangerous sites. But what drives them? What really makes them leave their families and hometowns? We go to the dizzying heights of these sites to see how these young people are building their futures as they reshape the Japanese capital.