When the Moors ruled a large part of what is now Spain -- they called it al-Andalus.
When they left, they took with them the region's musical traditions.
Those traditions became the basis for the "Andalusian music of Morocco."
Andalusian music is still performed in the city of Tangier, in northern Morocco.
It lies just a few miles from Spain, across the strait of Gibraltar.
The Orchestra of Tangier is a group of eight musicians and singers who keep Andalucian music alive.
They're now on their first-ever tour of the United States.
The World's Marco Werman asked some of the group's members to come perform in our studios.
The Orchestra performs in Boston tonight, then moves on to New York and Chicago.
Orchestra of Tangier tour dates:
BOSTON
Thursday, September 13 at 8:00 PM
Benjamin Franklin Institute of technology
NEW YORK CITY
Friday, September 14 at 6:30 PM
CUNY Graduate Center/Proshanky Auditorium
Sunday, September 16, at 3 pm
Central Park Summer Stage
CHICAGO
Monday, September 17 at 8:00 PM
Chicago Civic Center.