Complex sentence: In 1958, Lebanese speleologists discovered the upper galleries above the lower cave which have been accommodated with an access tunnel and a series of walkways to enable tourists safe access without disturbing the natural landscape.
Split into simpler sentences: In 1958, Lebanese speleologists discovered the upper cave above the lower cave. It has since been accommodated with an access tunnel and a series of walkways to enable tourists safe visitation without disturbing the natural landscape.