German built WWII bunker at Oddesund, Thyholm Peninsula, Denmark, Europe

oddesund thyholm peninsula germany bunker unesco heritage site historical architecture military structure denmark europe coastal defense concrete world war fortification preservation tourism cultural site nature landscape greenery artifacts war history scenic exploration educational travel heritage tourism engineering historical site relic outdoor research visit denmark historical significance cold war memorial local flora adventure landmarks history enthusiasts war relics structure conservation historical landmark field exploration site sightseeing danish history cultural heritage scenic views