cluster of hills southeast of Bonn, Germany. Volcanic in origin and actually about 40 in number, they rise on the right bank of the Rhine between Königswinter and the Cologne–Frankfurt am Main Autobahn. A popular tourist resort area and nature reserve, the hills form the northwestern part of the Westerwald region. The seven principal hills seen from Bonn, whence the name, are: Drachenfels (1,053 feet 【321 m】), reached by rack railway from Königswinter and surmounted by a ruined castle; Wolkenburg (1,066 feet); Petersberg (1,086 feet), with a motor road to the summit hotel that was the seat (1945–52) of the tripartite Allied High Commission; and, to the south, Grosser Ölberg (1,509 feet), the highest of the group; Löwenburg (1,493 feet); Lohrberg (1,427 feet); and Nonnenstromberg (1,101 feet). Quarries yield basalt for paving and for building (e.g., the Cologne and Limburg an der Lahn cathedrals). On the lower slopes behind Königswinter (King's Vineyards) are some of the northernmost vineyards in Europe.