Hajnówka as a small settlement started to change into a town after First World War along the development of wood industry.
The time of truly fast growth came however in 70’s of XX century.
The town doubled its inhabitants number, reaching 25 thousands, bringing them from nearby, mostly orthodox villages. The thing that makes visitors going to Białowieża stop in Hajnówka is orthodox church of Holy Trinity. It is one of the most beautiful orthodox temple in Poland. The building is quite impressive and has amazing architecture and interior. The layout of the temple is based on the use of irregular plan of intertwining softly modulated concrete shells and cross layout of parabolic cradles. Domes shaped as cones are supported by columns and topped with onion domes. The project was designed by architect professor Aleksander Grygorowicz from Poznań Technical University.