Río Muni is the largest part of Equatorial Guinea, being the part on the African mainland (the rest of the country is made up of islands, including Bioko, formerly Fernando Poo). Stamps for Río Muni were issued by Spain, which had control over the region from 1885 — 1968. The stamps were issued especially for Río Muni beginning in 1960 and lasting until the 1968 independence of the Republic of Equatorial Guinea.
The Río Muni stamps that were issued in this short time feature celebrations of various aspects of life in the area, including animals and traditional sculpture. The designs tend to be rather bold, simple and austere, reflecting a noble restraint and tasteful pride. The stamps or Río Muni, when seen in groups, are generally rather colorful as well — though most individual stamps feature only one main color.
See also: Equatorial Guinea rare stamps for philatelists and other buyers
Partly for this reason, some consider Río Muni stamps to best be collected in bunches rather than a few special singles. Stamps are for sale from Río Muni in multi-stamp lots quite often, so collectors who take this approach are generally in luck.