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unknown - Public Domain
NASA - Public Domain
Freeman, William Harry - Public Domain
English school of the 19th century - Public Domain
Georges Achard - Public Domain
Alan Light - CC BY 2.0
Stephencdickson - CC BY-SA 4.0
Public Domain
White House photo by Chris Greenberg - Public Domain
Ilya Haykinson - CC BY-SA 3.0
Artist not listed - Public Domain
nach einem Gemälde von E. Hader, herausgegeben 1882 von Sophus Williams Verlag Berlin. - Public Domain
G. Derby & J. T. White - Public Domain
Tom Marcello - CC BY-SA 2.0
Theodore Pietsch - CC BY-SA 4.0
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Valkeapää, Nils-Aslak
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unknown - Public Domain
Sleeman, W. H. (William Henry), Sir, 1788-1856
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NASA - Public Domain
Allen, Joseph P., 1937-
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unknown - Public Domain
King, Daniel P. (Daniel Putnam), 1801-1850
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Freeman, William Harry - Public Domain
Chase, William C. (William Curtis), 1895-1986
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King, Stephen, 1947-
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English school of the 19th century - Public Domain
Adams, William, Sir, 1783-1827
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Erasmus, Desiderius, -1536
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Georges Achard - Public Domain
Albert-Birot, Pierre.
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Alan Light - CC BY 2.0
Rocco, Alex, 1936-
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Stephencdickson - CC BY-SA 4.0
Soutar, William, 1898-1943
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Storm, Tempest
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Public Domain
Mouton, Alfred, 1829-1864
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White House photo by Chris Greenberg - Public Domain
Brown, Sarah, 1963-
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Ilya Haykinson - CC BY-SA 3.0
Seymour, Jane, 1951-....
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Brown, Wilson, 1882-1957
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Artist not listed - Public Domain
Braun, Alexander, 1805-1877
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Ricci, Matteo, 1552-1610
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Alibert, Jean-Louis-Marie, 1768-1837
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Ibáñez del Campo, Carlos, 1877-1960
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nach einem Gemälde von E. Hader, herausgegeben 1882 von Sophus Williams Verlag Berlin. - Public Domain
Auerbach, Berthold, 1812-1882
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Smith, Gustavus Woodson, 1822-1896
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Lazar, Prince of Serbia, approximately 1329-1389
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G. Derby & J. T. White - Public Domain
Leslie, Madeline, 1815-1893
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Tom Marcello - CC BY-SA 2.0
Adams, George, 1940-1992
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Lyssy, Rolf, 1936-
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About, Edmond, 1828-1885
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Theodore Pietsch - CC BY-SA 4.0
Holthuis, L. B.
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Sophronius, Saint, Patriarch of Jerusalem, approximately 560-approximately 638
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Anton Günther, Count of Oldenburg, 1583-1667