The Baška grapa is a 30 km long valley of the Bača river, which RUNS in northeast-southwest direction in the upper part, and then turns east-west in the southern part. Baška grapa is not only marked as a narrow valley, but also as sharply divided world on the north side above its valley floor, which rests on the long ridge of the Tolminsko Bohinj Mountains in the north and the Cerkljansko Hribovje in the south. The ridges do not exceed 2000 m, but the world is very vigorous due to the many narrow, limestone-cut side gorges and the main valley, as well as picturesque villages and hamlets on the slopes above the valley.

And it was here in the upper part of Baška Grapa in Podbrdo and Petrovo Brdo that the Mountain Marathon 4 Občin was born - the legendary GM4O and in it's honor The Friends of the Mountain Marathon 4 Občin club. The club was founded on July 21, 2006, when Jože Dakskobler - Jožko, as one of the first – runned/walked the marathon for three times in "one piece" and was the first to sign his name in the EXTREME section. Also the first entry into the club followed soon after, Doroteja Dakskobler, entered the GM4O club on September 20, 2006 and as the first woman in the EXTREME section on October 1, 2006. Soon after others followed and the membership of the club grew larger day by day. The GM4O Friends Club currently counts over 285 members.

There are more than 246 registered members in the regular section.

In the EXTREME section, according to the data so far, there are 9 women and 23 men, in total of 32 members.

Rules of GM4O Club

The Mountain Marathon of Four Municipalities is a great challenge for mountain runners. Completing a run in less than eight hours is a real challenge. But it can also become an challenge for all those who enyoy walking and think walking is very important, and even more, believing that I can do it myself. And for all such beliefs, joining the GM4O friends club is great opportunity.

To enroll in the GM4O club, the originally planned route must be completed, start and finish at Petrovo Brdo, there is also registration books in a special box on a pillar under the canopy.