Image from Wikimedia Commons
Konrad Jacobs, Erlangen - CC BY-SA 2.0
Allan Fleming - Public Domain
Heinrich Klaffs - CC BY-SA 2.0
David0825 - CC BY-SA 4.0
unknown - Public Domain
Montecruz Foto - CC BY-SA 2.0
Sam Levitan, via release to Peter G. Freund -
Harris & Ewing - Public Domain
Atelier Franz Werner, München - Public Domain
not stated - Public Domain
Sam Saunders - CC BY-SA 2.0
File photo, scanned and colorized by Tim Davenport - Public Domain
Library of Congress - Public Domain
TheGrayLion - CC BY-SA 4.0
RKO Radio - Public Domain
Public Domain
Image from Wikimedia Commons
Konrad Jacobs, Erlangen - CC BY-SA 2.0
Courant, Richard, 1888-1972
Image from Wikimedia Commons
Allan Fleming - Public Domain
Fleming, Allan
Image from Wikimedia Commons
Heinrich Klaffs - CC BY-SA 2.0
Korner, Alexis
Image from Wikimedia Commons
Derby, Thomas Stanley, Earl of, approximately 1433-1504
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Tyler, Comfort, 1764-1827
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David0825 - CC BY-SA 4.0
Pierson, Robert H.
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Anker, Albert, 1831-1910
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Cot, Pierre Auguste
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Alfvén, Hugo
Image from Wikimedia Commons
unknown - Public Domain
Billot, Jean-Baptiste, 1828-1907
Image from Wikimedia Commons
Montecruz Foto - CC BY-SA 2.0
Johansen, David, 1950-
Image from Wikimedia Commons
Sam Levitan, via release to Peter G. Freund -
Freund, Peter G. O. (Peter George Oliver), 1936-
Image from Wikimedia Commons
Harris & Ewing - Public Domain
Fuller, Alvan T. (Alvan Tufts), 1878-1958
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Gullstrand, Allvar, 1862-1930
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Ford, Ruth, 1911-2009
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Mirabeau, vicomte de, 1754-1795
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Atelier Franz Werner, München - Public Domain
Uhde, Fritz von 1848-1911
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Villeroi, Nicolas de Neufville, Seigneur de, 1542-1617
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not stated - Public Domain
Laestadius, L. L. (Lars Levi), 1800-1861
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Eda-Pierre, Christiane
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Sam Saunders - CC BY-SA 2.0
Williamson, Robin, 1943-
Image from Wikimedia Commons
File photo, scanned and colorized by Tim Davenport - Public Domain
Browder, Earl, 1891-1973
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unknown - Public Domain
Ambedkar, B. R. (Bhimrao Ramji), 1891-1956
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Schmidt, Jacques
Image from Wikimedia Commons
Library of Congress - Public Domain
Buck, Clayton Douglass, 1890-1965.
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TheGrayLion - CC BY-SA 4.0
Fox, Frederick, 1931-2011
Image from Wikimedia Commons
RKO Radio - Public Domain
Ober, Philip, 1902-1982
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unknown - Public Domain
Moulin, Jean-François Auguste 1752-1810
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Public Domain
Putnam, George Palmer, 1814-1872
Image from Wikimedia Commons
Murillo, Bartolomé Esteban, 1617-1682