Spaso-Efimiev Monastery, also known as the Saviour Monastery of St. Euthymius, is a fortified monastic complex located in the city of Suzdal, Russia. It is a UNESCO World Heritage Site and forms part of the Golden Ring of historic cities in Russia. Founded in the 14th century by Prince Boris Konstantinovich of Suzdal, the monastery became one of the richest and most powerful by the 16th century. The main structure within the complex is the Cathedral of the Transfiguration of the Saviour, adorned with frescoes by the renowned icon painters Gury Nikitin and Sila Savin. Over the centuries, the monastery has served various functions, including a religious retreat, a prison, and now as a museum. The walls and towers of the monastery, built for defense purposes, exude a medieval aura, while the surrounding landscape enhances the site's tranquil and majestic ambiance.