caverns
cav-erns
noun
Large, natural underground chambers or extensive series of interconnected caves, often dark and deep.
"The explorers ventured deep into the dark, echoing caverns."
Thesaurus
Synonyms: cavern out
cav-erns
Large, natural underground chambers or extensive series of interconnected caves, often dark and deep.
"The explorers ventured deep into the dark, echoing caverns."
Synonyms: cavern out