Mainzer Straße 28/30, former hotel and Soviet embassy building in Rolandswerth, Germany

Mainzer Straße 28/30 is a two-part building complex in Rolandswerth, begun in the mid-19th century and extended northward at the end of the 19th century with a five-axis wing articulated by pilasters. It stands on the west side of Bundesstraße 9, above the left arm of the Rhine and below the left-bank railway line, directly at the boundary with Oberwinter marked by the Rolandswerther Bach.

The building began as the Gasthof zum Rolandseck, a post-horse changing station recorded on an 1798 Rhine map as the Quantius-Haus. Arnold Karl Cornelius Groyen bought it in 1810, and his son added the southern plot in 1849 to turn the inn into the Hotel Rolandseck-Groyen. From December 1955 to February 1975 the former hotel housed the chancery of the Soviet embassy to West Germany, with 41 diplomats and 60 staff in 1965; part of it was used by the KGB residency in Bonn. It was sold in 1983 and converted into condominiums.

The building's name recalls the Gasthof zum Rolandseck, a tavern that stood here from the early 18th century and kept post horses. From 1955 to 1975 the former hotel housed the Soviet embassy's chancery, where 41 diplomats and 60 other staff worked in 1965. Part of the building was used by the KGB residency in Bonn.

The site is a protected cultural monument that can be viewed from the outside. Its location near Bonn allows you to include it with visits to other nearby attractions.

The building's site was long a post-horse changing station on the road between Wittgen and Oberwinter, and a 1798 Rhine map by Wiebeking labels it the "Quantius-Haus". From 1955 the KGB's Bonn residency occupied part of the former hotel alongside the Soviet embassy staff.