Architect Stefan Kurylowicz, his associate Jacek Syropolski, and two other Poles died Monday after the two light aircraft they were flying in collided with one another over the Principality of Asturias in northern Spain. The names of the other two victims have not yet been made public.

The accident is the worst aviation disaster in Spain in the last five years.

At the time of the accident the sky was filled with dense clouds, meaning visibility was reduced to less than one kilometer, local media in Asturias reported.

One of the planes crashed into an empty building in an airport and the other fell into a forest.

The two planes were flying from San Sebastian to Vilar da Luz near Porto, Portugal, together with a third plane, which landed safely at Asturias airport.

Stefan Kurylowicz was an award-winning architect who lectured at The Warsaw University of Technology. He had joined forces with Jacek Syropolski to create the architectural firm Kurylowicz & Associates. In Warsaw, the firm's current projects include a new office building for national airline Lot, the Focus Filtrowa office building, and the Wolf Bracka department store. The company is also working on the municipal stadium in Białystok.

Thomas Kolasa