Minsk

Lake Narach
is the largest lake in Belarus, located about 160 km north of Minsk.

Brest is a regional capital on the border with Poland and is rich with history from both the Soviet times and before. You can see a Brest Hero Fortress, perhaps the most impressive Soviet monument ever built. You can get there by train ~20 daily trains running from Minsk at $5-20USD. It takes 3-4 hrs by train.

Grodno is a border town in north-west Belarus, near Kuźnica-Białostocka in Poland.