From 1988, Bra is twinned with spreitenbach, a town in the canton of Aargau of the Swiss Confederation. It is located at 421 m. of altitude at sea level and consists of approximately 9.000 inhabitants (of which one third of foreign origin) distributed over a territory of 860 ha. occupied for about a third by woods. It is defined as the "Manhattan" of the canton of Aargau for the characteristic skyscrapers of the northwest that overlook an ancient well-preserved and preserved village. The town is surrounded by forests and dominated by the lush hill of Heitersbarg.
The origins of Spreitenbach are very old since archaeological finds show the presence of urban settlements already in the stone age. His name however appears in public records around the 1124. Its oldest building dates back to 1500, the "Chloster-Spycher" (cloister barn), which shows with its name a clear subjection to the Cloister of Wettimgen. The Catholic and Protestant communities maintain excellent relations, so much so that the Protestant church (built in 1639) has been used by both parish communities up to 1904, a period in which the Catholic Church was erected.