HEINRICH HERTZ (1857-1894).
MARIE CURIE (1867-1934).
HARRIET QUIMBY (1875-1912).
ANDRE MARIA AMPERE
ANDRE MARIE AMPERE
GUSTAV ROBERT KIRCHHOFF
MAX PLANCK (1858-1947).
STANLEY & LIVINGSTONE, 1871.
NIELS BOHR (1885-1962).
CLAUDE BERNARD (1813-1878).
KARL FRIEDRICH GAUSS
ENGELS AND MARX.
FRIEDRICH ENGELS (1820-1895).
NAINI JUNCTION STAMP, 1911.
U.S. POSTAGE STAMP, 1918.
JOHANN GOTTLIEB FICHTE
WRIGHT BROTHERS.
JUAN PONCE de LEON
U.S. POSTAGE STAMP, 1945.
AMELIA EARHART (1897-1937).
POSTAGE STAMP, 1856.
ANTONIO DE MENDOZA
AUGUSTE COMTE (1798-1857). French philosopher. On a French postage stamp, 1957.
BERTRAND RUSSELL (1872-1970).
FRANCISCO DE ORELLANA
PEDRO MENENDEZ DE AVILES
MAIMONIDES (1135-1204).
NICOLAUS COPERNICUS
GOTTFRIED VON LEIBNIZ
SIR MARTIN FROBISHER
HENRY HUDSON (d. 1611).
POSTAGE STAMP, 1918.
SRINIVASA RAMANUJAN
PONY EXPRESS COVER, 1861.
EDWARD JENNER (1749-1823).
GERHARD HANSEN (1841-1912).
TYCHO BRAHE (1546-1601).
VASCO NUNEZ DE BALBOA
ROBERT H. GODDARD
ALBERT EINSTEIN (1879-1955).
FRANCISCO PIZARRO
JOS GALVEZ (1729-1787).
GADSDEN PURCHASE
U.S. POSTAGE STAMP, 1869.
HEINRICH HERTZ (1857-1894)
JOSEPH LISTER (1827-1912).
GEORGE WASHINGTON CARVER
BENJAMIN BANNEKER
KARL LANDSTEINER (1868-1943).
JEAN HENRI FABRE (1823-1915).
SOREN KIERKEGAARD
ROBERTO CLEMENTE
ROBERT FALCON SCOTT
JOSEPH PRIESTLEY (1733-1804).
BARUCH SPINOZA (1632-1677).
JEAN JACQUES ROUSSEAU
ANTONIO PIGAFETTA
GIOVANNI DA VERRAZZANO
LAZZARO SPALLANZANI
JOHN DEWEY (1859-1952).
JAN MATZELIGER (1852-1889).
JUAN DE ZUMARRAGA
BARTOLOMEU DIAS
VASCO da GAMA (1469?-1524).
CABEZA DE VACA (c1490-c1557).
1931 AIRMAIL LETTER
CLARA BARTON (1821-1912).
GEORGES MELI S (1861-1938).
SUN YAT-SEN (1866-1925).
VICTORIA OF ENGLAND
IGNAZ SEMMELWEIS (1818-1865).
ABRAHAM LINCOLN
HEINRICH HEINE (1797-1856).
JACKIE ROBINSON (1919-1972).
FREDERIC REMINGTON
HEINRICH RUDOLPH HERTZ (1857-1894). German physicist.
RALPH WALDO EMERSON
JOHN JAMES AUDUBON
LUTHER BURBANK (1849-1926).
HARRIET TUBMAN (c1820-1913).
LUCY STONE (1818-1893).
IDA BELL WELLS (1862-1931).
AVICENNA (IBN-SINA)
AVICENNA, (IBN-SINA)
PEDRO ALVARES CABRAL
HERNANDO DE SOTO
IMMANUEL KANT (1724-1804).
GIL EANES (fl. 15th CENTURY).
HOMESTEAD ACT
FIRST POSTAGE STAMPS.
STAMP, 1845.
CONFEDERATE STAMPS, 1863.
MULREADY ENVELOPES, 1840.
ALEXANDER GRAHAM BELL
WILLA CATHER (1873-1947).
ITALIAN STAMP, 1959.
MEXICAN FLAG, 1840s.
DAVID LIVINGSTONE (1813-1873).
U.S. STAMP: FRANKLIN, 1898.
JEAN-FRANCOIS CHAMPOLLION
PAUL LAURENCE DUNBAR
PAUL DUKAS (1865-1935).
HAYM SALOMON (c1740-1785).
SIR HENRY MORGAN
GEORGE WASHINGTON.
JUN PERO SERRA (1713-1784).
BERNARDO de GALVEZ
MARTIN LUTHER KING, JR.
SAM HOUSTON (1793-1863).
HEINRICH HERTZ (1857-1895).
JOSE de ANCHIETA (1534-1597).
KING GEORGE VI STAMP, 1943.
WINSTON CHURCHILL
STAMP: BICYCLE POST, 1894.
SOVIET COSMONAUTS, 1960s.
FRANCES ELIZABETH WILLARD
ALFRED WEGENER (1880-1930).
SAMUEL CLEMENS POSTCARD.
BARTOLOME de LAS CASAS
ANDRE MALRAUX (1901-1976).
VASCO NUNEZ de BALBOA
SIEUR DE LA SALLE
SUSAN B. ANTHONY (1820-1906).
MEXICO: AZTEC ILLUSTRATIONS.
WASHINGTON IRVING
HENRY WADSWORTH LONGFELLOW
JAMES RUSSELL LOWELL
DANIEL CHESTER FRENCH
STEPHEN COLLINS FOSTER
ELIAS HOWE (1819-1867).
CRAWFORD WILLIAMSON LONG
MARK HOPKINS (1802-1887).
CHARLES WILLIAM ELIOT
JAMES WHITCOMB RILEY
GILBERT STUART (1755-1828).
AUGUSTUS SAINT-GAUDENS
JOHN PHILIP SOUSA (1854-1932).
EDWARD ALEXANDER MacDOWELL
ETHELBERT NEVIN (1862-1901).
CYRUS HALL MCCORMICK
SAMUEL F.B. MORSE (1791-1872).
WALTER REED (1851-1902).
HORACE MANN (1796-1859).
BOOKER T. WASHINGTON
SLAVERY: 13TH AMENDMENT.
PONY EXPRESS: STAMP, 1960.
PONY EXPRESS: STAMP, 1940.
1872 ESSAY PROOF.
JAMES MADISON STAMP.
JOHN GREENLEAF WHITTIER
WALT WHITMAN (1819-1892).
JAMES A. McNEILL WHISTLER
ELI WHITNEY (1765-1825).
JAMES FENIMORE COOPER
SAMUEL LANGHORNE CLEMENS
CHIEF JOSEPH (1840-1904).
GEORGE H. RUTH (1895-1948).
EDWARD TEACH (d. 1718).
PEDRO DE VALDIVIA
D.W. GRIFFITH (1875-1948).
GEORGE LOWTHER (fl. c1720). English pirate. On a British Virgin Islands postage stamp, 1970.
QUEEN ELIZABETH II: STAMP.
FINNISH ENVELOPE, 1845.
UNCLE SAM COVER, c1846.
U.S. STAMP: FRANKLIN, 1903.
'CENTER LINE BLOCK', 1908.
DIEGO de ALMAGRO (c1475-1538).
GUILLAUME DE MACHAUT
LEONARDO DA VINCI
Heinrich Hertz's mirror experiment.
WORLD WAR II: IWO JIMA.
FIRST POSTAGE STAMP, 1842.
POSTAGE STAMP: U.S. & CHINA.