Through the rainforests of central america stretches one of the biggest manmade marvels on the planet, the panama canal. A colossal engineering project aims to double the canal's capacity, almost a century after it was inaugurated. The panama canal owes its success to four key inventions found in a series of landmark canals. At the heart of each lies a major technological breakthrough that allows ever bigger ships to navigate landlocked areas. One by one travelling up the scale, we'll reveal the incredible stories behind these structures, and the inventions that allowed each one to carry tonnes more cargo than the last -- four ingenious leaps forward, from big, to bigger, into the americas' biggest.

Through the rainforests of central america stretches one of the biggest manmade marvels on the planet, the panama canal. A colossal engineering project aims to double the canal's capacity, almost a century after it was inaugurated. The panama canal owes its success to four key inventions found in a series of landmark canals. At the heart of each lies a major technological breakthrough that allows ever bigger ships to navigate landlocked areas. One by one travelling up the scale, we'll reveal the incredible stories behind these structures, and the inventions that allowed each one to carry tonnes more cargo than the last -- four ingenious leaps forward, from big, to bigger, into the americas' biggest.

In the early 1970s, Sixto Rodriguez was a Detroit folksinger who had a short-lived recording career with only two well received but non-selling albums. Unknown to Rodriguez, his musical story continued in South Africa where he became a pop music icon and inspiration for generations. Long rumored there to be dead by suicide, a few fans in the 1990s decided to seek out the truth of their hero's fate. What follows is a bizarrely heartening story in which they found far more in their quest than they ever hoped, while a Detroit construction laborer discovered that his lost artistic dreams came true after all.