Venus volcano (IMAGE) University of California - Riverside Caption Maat Mons is a massive shield volcano on the planet Venus and the planet's second-highest mountain and highest volcano. Credit NASA/JPL Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.