This row of houses covers three distinct architectural styles and today house the Museum of Architecture (one or all do, I can't quite work that out even after much research). The building on the right dates from the 15th century and is the oldest stone residential building in Riga. The center building was constructed in the 17th century, while the green building on the end is from the 18th century. They were so named after the Three Sisters in Tallinn http://www.pbase.com/helenpb/image/144718698.

These buildings presented a real challenge to photograph between the very narrow street, the many people around, the uncooperative sun, power lines right in front and suspended street lights as well ;-).