Photographs courtesy of:

© Allentown Morning Call/Getty (10). © Archive Photos/Stringer/Getty (4). © Bernard Barcos/Alamy (21). © Classic Image/Alamy (18 left). © Everett Collection Inc/Alamy (13, 14). © GL Archive/Alamy (19). © Peter Harholdt/Collections of The Franklin Institute (9). © INTERFOTO/Alamy (20). © Library Company of Philadelphia (8). © London Metropolitan Archives (City of London)/Heritage Image/age fotostock (12). © National Portrait Gallery/Smithsonian Institution (15). © North Wind Picture Archives/Alamy (1, 5, 6). © Photo 12/Alamy (17). © The Picture Art Collection/Alamy (7). © Smithsonian Institution Archives (2). © Trumbull Collection/Yale University Art Gallery (16). © Marek Uliasz/Alamy Stock Photo (3). © Universal History Archive/Getty (18 right). © Werner Wolff/Getty (11).