Projects to build a museum in a historic Polish city square and to recover an orchard in Spain have been named the joint winners of the European Prize for Urban public space 2016.

The annual award celebrates the creation, recovery and improvement of public spaces “as clear indicators of the democratic health of our cities”. This year, 276 candidatures from 33 countries were submitted to the prize, and the winners were announced at a ceremony last night (4 July).

The Dialogue Centre in Szczecin is an underground museum, the roof of which forms part of the city’s Solidarity Square. The centre – part of the National Museum – charts the city’s recent history, including the anti-Communist rallies which took place at the site in 1970, which led to the deaths of 16 protesters.

architecture studio KWKPromes wanted to create “an urban design hybrid which encloses the space as a quarter, while retaining the values of open public space”.

The design, completed in 2014, eliminates any barriers encountered at the meeting point of the square and the city, reopening the site and complementing the nearby cultural landmarks, such as Estudio Barozzi Veiga’s award-winning Konzerthaus.

In a statement, the studio said: “For years, this had been a square by name only, with vague borders, open frontages, burdensome busy street neighbourhoods and the absence of a defined function, despite the dominating one to commemorate the events of December 1970.

“Our goal was not only to design the museum, but to transform the dysfunctional, degraded space to a whole public space facilitating human interactions.”

The Dialogue Centre shares the European Prize with the recovery of the Thermal Orchards in Caldes de Montbui, Spain, which was completed last year.

The gardens were historically irrigated with thermal water, but had deteriorated due to wastewater contamination. Designers Elena Albareda Fernandez, Jordi Calbetó Aldomà and Marta Serra Permanyer repaired the irrigation system and took the opportunity to open up a network of pedestrian pathways through the grounds, creating an open public space.

A new pool was added to accumulate and cool the surplus water from the thermal spas, and a walkway was created over the main canal where wastewaters are channeled.

“The process recognises the key value of traditional water management as intangible heritage towards urban sustainability,” said the design trio.

The European Prize jury – led by architect Enric Batlle – also gave special mentions to a memorial garden in Kiev, an elliptical WWI monument in Ablain-Saint-Nazaire, and the city of Copenhagen for “its firm and persistent commitment to public space that gives priority to cyclists and pedestrians.”