hedera helix grows on the wall of the historic flak tower flakturm humboldthain. berlin, germany

anti-aircraft architecture attractions berlin berliners blue building bunker system city europe european flak tower flakturm germany historic history observation deck park path sights stairs summer tourism town travel ancient background botany commonly called ivy cute flora floral green hedera helix leaf leaves lion natural nature organic plant stone traditional wall grows humboldthain species flowering family araliaceae