Kaliningrad Stadium was built for Russia 2018 on Oktyabrsky Island, right in the heart of Kaliningrad.
The selection of Kaliningrad as one of the 11 Russian host cities prompted the local authorities to develop the island, which for many centuries had been a wilderness, left largely untouched.
The island's soft clay protected water-bird colonies from the port city's industrial development.
Environmentalists are voicing their concerns over the construction of the stadium on what they say is an ecologically sensitive site.
“It was a little corner of heaven in the city, where birds lived,” ecologist Alexandra Koroleva said.
Koroleva said the site was a typical delta island, with peat and a wetland reed-bed that used to serve as a natural filter for the Pregolya river.
“Pregolya river creek is very polluted, so of course it could use any filter, any possibility for cleaning,” Koroleva said.
The Deputy Chairman of Kaliningrad regional government, Alexander Rolbinov, said the site had been difficult to build on “from the construction point of view.”
“But today, as all the construction work is finished, I can say that it's hard to imagine a better place,”
Some residents disagree.
“Before it was just a swamp and I think the ground will start sinking with time and the stadium will start falling apart,” a 22-year-old resident Alexander Frolov said.
Kaliningrad is Russia's westernmost city.
Cut off from the Russian mainland, it sits between Lithuania and Poland.
Founded in 1255 by the Teutonic Order of knights, the city was called Koenigsburg and was capital of
Germany's East Prussia until Soviet troops took it over in 1945.
Josef Stalin expelled ethnic Germans from the area and renamed the city in honour of a prominent Bolshevik, Mikhail Kalinin.
The ancient city was largely destroyed during the war.
Despite its location in the heart of Europe, the area struggled economically in the 1990s, but has been undergoing a renaissance in recent times.
The 35,000-capacity stadium is one of the smaller venues in this World Cup but will host four group stage games: Croatia versus Nigeria (16th June), Serbia versus Switzerland (22nd June), Spain versus Morocco (25th June) and England versus Belgium (28th June).