Rui peak is in Riu mountain. It is 1706 m high. One of the starting points is Lomnitsa village. The walk is about 3 hours and 30 min. The path is wide and with a small slope. After the hut steep climbing strats and it takes about 40 min. The peak is on the border between Bulgaria and Serbia. It a good idea to have your identification papers with you as they might be checked by the border guards.