Venus exploration is the study and exploration of the planet Venus, which is the second planet from the sun in our solar system. Venus is often referred to as Earth's "sister planet" due to its similar size and composition. Research in this area focuses on understanding Venus' geology, atmosphere, and surface conditions, as well as the possibility of past or present life on the planet. Exploration of Venus has included missions by space agencies such as NASA, the European Space Agency, and the Soviet Union, with a variety of spacecraft, landers, and orbiters being sent to study Venus in more detail. The extreme conditions on Venus, including its thick atmosphere and surface temperatures hot enough to melt lead, make exploration of the planet a challenging but rewarding endeavor for scientists.