Mercury resembles our moon - heavily cratered. No atmosphere to moderate temperature changes Mercury appears from Earth as a bright star to the naked eye - but always near the Sun in the sky. Tricky to spot - always close to the glare of the sun in evening or morning. AU Surface of Venus is hidden by clouds - our maps are all from radar. Venus has a dense CO 2 atmosphere - the pressure at the surface is 90X that on Earth.
Earth has a mild greenhouse effect - it actually keeps the average temperature above freezing.