https://commons.wikimedia.org/wiki/File:Eratosthenes_%26_measurement_of_the_Earth.png
Eratosthenes & measurement of the Earth
taken from Spanish wikipedia
Orginal text:Imagen:Eratostenes-circunferencia-polar.png De http://enciclopedia.us.es/index.php/Imagen:Eratostenes-circunferencia-polar.png {GFDL}
17:05, 8 March 2011

Original filename:
https://upload.wikimedia.org/wikipedia/commons/b/be/Eratosthenes_%26_measurement_of_the_Earth.png