Under Opens as Europe's First Underwater Restaurant
CONFIRMED83% CONFIDENCEWikipedia[2] gives 20 March 2019, and the date holds up against the contemporary press: Aftenposten ran "Nå åpner Under. Slik ser det ut i havdypet" on 19 March 2019, the eve of the opening. Secondary coverage that says only "early 2019" or "launched in 2019" does not narrow it further.
A 34-metre concrete tube is half-sunk off Norway's southernmost point and opens as a restaurant, five and a half metres down, with an 11-metre window onto the seabed. Between services it works as a marine research station.
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