The Chacaltaya laboratory at 5220 m a.s.l.

Cosmic rays physics is currently study with rather sophisticated detectors running in a variety of either experimental conditions or atmospheric depths in the world. In this paper we present some cosmic ray physics investigations at Chacaltaya Laboratory, (Bolivia, 5220 m a.s.l.) and we describe the main properties of the observed features of high-energy nuclear interaction phenomena of cosmic rays, with particular emphasis on some experimental observations by using the emulsion chamber technique. A discussion on the past and present achievements as well as the future prospects of the high altitude mountain laboratories for cosmic ray physics as Chacaltaya is presented. [ABSTRACT FROM AUTHOR]