Complex sentence: The city was built on both sides of a straight on the main road leading from Vilnius to Minsk, dividing it into two sections the "lower neighborhood" along the river and the "upper neighborhood" toward the hills.
Split into simpler sentences: The city was built on the main road leading from Vilnius to Minsk. It is divided into two sections: the "lower neighborhood" along the river and the "upper neighborhood" toward the hills.