Image from Wikimedia Commons
Jamesvalentiopera - CC BY-SA 3.0
John Kunkel Small - Public Domain
Charles Ernest Butler - Public Domain
Mathew Brady - Public Domain
Félix Vallotton - Public Domain
Harris & Ewing, photographer - Public Domain
unknown<br/> - Public Domain
Public Domain
New York World-Telegram and the Sun staff photographer: Albertin, Walter, photographer. - Public Domain
Elias223 - CC BY-SA 3.0
Sergei ~ 5of7 - CC BY-SA 2.0
Artist unknown - Public Domain
Anomymous - Public Domain
unknown - Public Domain
Image from Wikimedia Commons
Sanger, Frederick, 1918-2013
Image from Wikimedia Commons
Davy, John, 1790-1868
Image from Wikimedia Commons
Peixoto, Floriano, 1839-1895
Image from Wikimedia Commons
Ritchie, John William, 1808-1890
Image from Wikimedia Commons
Jamesvalentiopera - CC BY-SA 3.0
Valenti, James
Image from Wikimedia Commons
Henson, Leslie
Image from Wikimedia Commons
Horsford, Eben Norton, 1818-1893
Image from Wikimedia Commons
John Kunkel Small - Public Domain
Small, John Kunkel, 1869-1938
Image from Wikimedia Commons
Cézanne, Paul, 1839-1906
Image from Wikimedia Commons
Charles Ernest Butler - Public Domain
Baylis, Lilian, 1874-1937
Image from Wikimedia Commons
Nicephorus II Phocas, Emperor of the East, 912-969
Image from Wikimedia Commons
Mathew Brady - Public Domain
Hazen, William Babcock, 1830-1887
Image from Wikimedia Commons
Mantegna, Andrea, 1431-1506
Image from Wikimedia Commons
Urquidi, Víctor L.
Image from Wikimedia Commons
Brown, Basil, 1888-1977
Image from Wikimedia Commons
Impey, Elijah, Sir, 1732-1809
Image from Wikimedia Commons
Félix Vallotton - Public Domain
Vielé-Griffin, Francis, 1864-1937
Image from Wikimedia Commons
Harris & Ewing, photographer - Public Domain
Compton, Wilson Martindale, 1890-1967
Image from Wikimedia Commons
unknown<br/> - Public Domain
Blake, Eli Whitney, 1836-1895.
Image from Wikimedia Commons
Public Domain
Joachim, of Fiore, approximately 1132-1202
Image from Wikimedia Commons
Doob, Joseph L.
Image from Wikimedia Commons
New York World-Telegram and the Sun staff photographer: Albertin, Walter, photographer. - Public Domain
Algren, Nelson, 1909-1981
Image from Wikimedia Commons
Elias223 - CC BY-SA 3.0
Blanchard, Esprit, 1696-1770
Image from Wikimedia Commons
Forbes, W. A. (William Alexander), 1855-1883
Image from Wikimedia Commons
Sergei ~ 5of7 - CC BY-SA 2.0
Smith, Rex
Image from Wikimedia Commons
Gonzales, Alberto R., 1955-
Image from Wikimedia Commons
Artist unknown - Public Domain
Martin, Thomas Bryan, 1731-1798
Image from Wikimedia Commons
Shakur, Assata
Image from Wikimedia Commons
Anomymous - Public Domain
Teitelbaum, Joel
Image from Wikimedia Commons
unknown - Public Domain
Foster, Myles Birket, 1825-1899