This past winter, workers pulling up the gymnasium floor during renovation work at Turku's Cathedral School uncovered the remains of two medieval houses and a section of street.
The ruins were buried in the wake of a great fire in September 1827 that destroyed 75% of the city, including the medieval Cathedral Quarter and nearly all of its mostly medieval structures.
The surprisingly well-preserved remains are of a medieval complex of the cellars and parts of the first floors of stone-built houses dating back to the 14th century.
Finding ruins under the gym floor did not come as a surprise to archaeologists. Located adjacent to the Aboa Vetus history museum, also built over medieval ruins, the plot on which the Cathedral School stands has been the site archaeological digs for the past three years.
Similar remains have been uncovered in the schoolyard.
It was also known from old maps that there were two upper-class stone dwellings in the area along the banks of the Aura River, just a stone's throw from the Cathedral.
"What was surprising is how well preserved these are. Traces of these were noticed by the archaeologist Juhani Rinne when the gym was built at the beginning of the 1900s, but now the picture has come into focus," the leader of the dig team, Kari Uotila told Yle in February.
Guided tours of the site are to begin next month. Between 12 and 26 June, tours will be available daily Tuesday-Saturday 10AM to 6PM, and 27 June - 1 July 10AM to 8PM. The tours are free of charge.