Hardeep Singh Kohli goes behind the scenes at some of London's museums and galleries to find the hidden paintings of the sailors, slaves and scholars who shaped the city. Through the art, Hardeep discovers how the Thames became the entry point for thousands of foreigners in the 18th and 19th centuries, and how they established vibrant docklands communities. He explores how Irish migrants fleeing the potato famine helped build the city we know today but paid a heavy price for moving here, and discovers the portrait that inspired the slavery-abolition movement and helped change the course of history.