grand caverns - grottoes virginia usa

area attraction brown calcite cave cavern caverns caves chamber chambers dark deep deposit deposits dry earth earthen enclosed exploration explore exploring flow flowstone flowstones formation formations geological geology grand grottoes ground historical history limestone mineral minerals natural old oldest orange pillars red rock rocks rocky room rough sedimentary shield shields space stalactite stalactites stalagmite stalagmites states stone stones structure structures tan texture textures tone tones under underground united virginia white within yellow