The final episode focuses on the construction of the Hoover Dam during the Great Depression of the 1930s, focussing in particular on the ruthless pace set by Frank Crowe, the builder, whose eagerness to complete the project well before schedule and subsequent exploitation of the workforce (who were desperate for any employment and were forced to accept conditions of extreme hardship in the process) would result in both many deaths and the (eventual) construction of a new city to house the workers.