closed arched entrance to the tunnel leading to hydrogen sulfide karst lake proval in night, pyatigorsk, russia

arched architecture art attraction bender bronze building caucasian chair character city closed culture entrance established europe european evening fake famous figure hydrogen hydrosulphuric inscription iron karst krai lake landmark leading literary man mashuk metal monument mount night old ostap outdoor outside people place proval pyatigorsk russia sculpture selling statue stavropol stone sulfide tickets tourism tourist travel tunnel underground wall