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NASA - Public Domain
uncertain - Public Domain
Library of Congress - Public Domain
CT State Library - CC BY 2.0
Public Domain
Mathew Brady - Public Domain
unknown - Public Domain
Metropolitan Transportation Authority of the State of New York - CC BY 2.0
RICHARDJRBP - CC BY-SA 3.0
unknown photographer - Public Domain
Pnuao - Public Domain
Anonymous - Public Domain
F. Cutekuist - Public Domain
H-stt - CC BY-SA 4.0
SPDuffy527 - CC BY-SA 3.0
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NASA - Public Domain
Roman, Nancy Grace, 1925-2018
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Day, Doris, 1922-
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Parek, Lagle, 1941-
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uncertain - Public Domain
Pratt, Lorus Bishop, 1855-1923
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Library of Congress - Public Domain
Soto, Gary.
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CT State Library - CC BY 2.0
Rowland, John G., 1957-
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Proctor, Thea, 1879-1966
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Racine, Louis, 1692-1763
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Public Domain
O'Donnell, Kenneth P., 1924-1977
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Colden, Cadwallader D. (Cadwallader David), 1769-1834
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Seyfried, Ignaz von, Ritter, 1776-1841
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Devine, Samuel L. (Samuel Leeper), 1915-1997
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Mathew Brady - Public Domain
Foster, Lafayette S. (Lafayette Sabine), 1806-1880
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unknown - Public Domain
Smith, William, 1797-1887
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Marlborough, James Ley, Earl of, 1550-1629
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Metropolitan Transportation Authority of the State of New York - CC BY 2.0
Vanden Heuvel, William J. (William Jacobus), 1930-
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Siegel, Sol C., 1903-1982
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Scarpetta, Eduardo, 1853-1925
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Howe, John, 1630-1705
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MacNab, Allan Napier, 1798-1862
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RICHARDJRBP - CC BY-SA 3.0
Lasso, Gloria
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Biseo, Cesare, 1843-1909
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unknown photographer - Public Domain
Veiller, Bayard, 1869-1943
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unknown - Public Domain
Fox, Fontaine, 1884-1964
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Pnuao - Public Domain
Sasakawa, Ryōichi, 1899-1995
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Gwynne, H. A. (Howell Arthur), 1865-1950
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Anonymous - Public Domain
Monk, James, Sir, 1745?-1826
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F. Cutekuist - Public Domain
Watson, John Crittenden, 1842-1923
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H-stt - CC BY-SA 4.0
Hunt, John Dixon.
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SPDuffy527 - CC BY-SA 3.0
Casper, Gerhard