You are a US citizen and: 1  You are a first time applicant age 18 or older. 2  OR your most recent U.S. Passport was issued when you were under age 16. 3  OR your previous U.S. passport was issued more than 15 years ago.
Cave formations are called speleothem, from the Greek word spelaion, cave and thema meaning deposit. Almost all of them are made of calcite, the crystal of calcium carbonate. Different minerals and different movements in the water account for an incredible variety of cave formations.
Cave painting. Cave of Altamira, near Santander, Spain. Cave paintings (also known as parietal art) are painted drawings on cave walls or ceilings, mainly of prehistoric origin, to some 40,000 years ago (around 38,000 BCE) in Eurasia. The exact purpose of the Paleolithic cave paintings is not known.