en.wikipedia.org/wiki/Siena_Cathedral
google:
"The exterior and interior are constructed of white and greenish-black marble in alternating stripes, with addition of red marble on the façade. Black and white are the symbolic colors of Siena, etiologically linked to black and white horses of the legendary city's founders, Senius and Aschius. "
google:
"The exterior and interior are constructed of white and greenish-black marble in alternating stripes, with addition of red marble on the façade. Black and white are the symbolic colors of Siena, etiologically linked to black and white horses of the legendary city's founders, Senius and Aschius. "