Architecture, Building and Structure Design A3 Advanced Architecture Apartments by STARH The idea was to create a building which was harmoniously fit in its environment. Two elements set the architectural concept – the mountain and the city. A3 is located in the border area where these two elements overflow into one. Due to its position – in the part of Sofia where the modern and interesting buildings are, A3 is designed to be contextual and innovative. The other dominant component of the environment is the mountain, peeking into the building. The logical result from these elements is the dynamic and modern shape of the building, while its function was never harmed.