Easy to find with Garmin GPS, not with google maps could not find it But Bing Maps could. From Siena, take the main road towards Arezzo (Viale Pietro Toselli which becomes Strada Statale 73 Levante just south of Via Aretina/Strada di Pieva a Bozzone. Turn Right onto Viele Europa into a light industry business area a little after the Via Aretina intersection. Follow Viele Europa around the corner until you come to Via Delle Arti, which is a Dead end. At the end of the Via Delle Arti , to the left, is a large 2 or 3 story business building. The mosque is located under the ground floor closest to the street, accessible by a service road that takes you down below ground level. Do not go inside to the second floor to office #4.