In an interview with Sputnik, Sebastian Kuropatnicki, representative of the local municipality, revealed the contents of the recent discovery.
"We found a letter of the local banker who corresponded with Berlin on the best possible location for a training school of the German National Socialist Workers' Party!" Kuropatnicki told Sputnik.
According to Kuropatnicki, the "time capsule" also contained German coins, newspapers and photos of the city.
"The German newspapers are just perfect, they look like they have just been printed. It is very interesting to read them," the official said.
The first information about the "time capsule" came up in 1997, when a book was published about the history of the city. It said that in 1934 the city celebrated its 60th anniversary and "letters to the future" were written as a part of celebrations.
In 2015, the city's mayor Krzysztof Zacharzewski initiated a search for the mysterious "time capsule" and motivated locals to take part in the search operation.
In Kuropatnicki's opinion, the "time capsule" is not only a "blast from the past," but also a message from a completely different country that in 1939 started World War II.
"And this is the part of the history of our city, whether someone like it or not," the official concluded.