  Wide field BVI photometry and $^{12}$CO(1$\to$0) observations are presen ted
in the region of the open cluster NGC 6520 and the dark molecular cloud
Barnard~86. From the analysis of the optical data we find that the cluster is
rather compact, with a radius of 1.0$\pm$0.5 arcmin, smaller than previous
estimates. The cluster age is 150$\pm$50 Myr and the reddening
E$_{B-V}$=0.42$\pm$0.10. The distance from the Sun is estimated to be
1900$\pm$100 pc, and it is larger than previous estimates. We finally derive
basic properties of the dark nebula Barnard 86 on the assumption that it lies
at the same distance of the cluster.

Astrophysics