1. Definition: Cave paintings, also known as parietal art, are painted drawings on cave walls or ceilings, primarily of prehistoric origin, found in various parts of the world.

2. Oldest Known Cave Paintings: The oldest known cave paintings are over 40,000 years old (Art of the Upper Paleolithic), found in the El Castillo cave in Cantabria, Spain.

3. Locations: Significant cave paintings can be found in various parts of the world including Europe (France, Spain), Africa (Algeria, Libya), Asia (Indonesia), and the Americas (Argentina, Mexico).

4. Subjects: Most cave paintings depict animals such as bison, horses, deer, and mammoths. There are also human figures, symbols, and handprints. The specific meanings of these paintings remain a subject of debate among archaeologists and anthropologists.

5. Techniques: Prehistoric artists used various techniques, including drawing, painting, and engraving. Paints were made from natural materials like mineral pigments, ochres, burnt bone meal, and charcoal, mixed with water, blood, animal fats, or plant juices.

6. Famous Sites:

• Lascaux Cave, France: Known as the "Sistine Chapel of Prehistoric Art", the Lascaux caves house a significant number of paintings, most of which are over 17,000 years old.
• Altamira Cave, Spain: The Altamira cave paintings, made by Paleolithic people around 14,000 years ago, are renowned for their high quality and remarkable color preservation.
• Chauvet Cave, France: These caves contain some of the earliest known cave paintings, dating back to around 32,000 years ago. The quality, quantity, and preservation of the drawings led to the site's designation as a UNESCO World Heritage site.

7. Purpose: The purpose of cave paintings is not clear; they may have served ritual or ceremonial purposes, or could have been a way to communicate or record events. Their exact significance remains a mystery.

8. Discovery and Study: Cave paintings have been discovered and studied since the early 19th century. However, many remain inaccessible to the public to preserve their integrity. Replicas, such as Lascaux II, have been created for public viewing and study.

9. Threats: Cave paintings are threatened by factors like climate change, human interference, and microbiological damage. Preservation of these invaluable pieces of human history remains a significant challenge for modern societies.