Venus and Earth are considered sister planets because of their similar radius and mass, and proximity to each other. These two planets most likely had similar atmospheres at their formation. However, the present Venus is completely different from Earth. For example, the surface of Venus is not an ideal place for life due to its extreme atmospheric pressure and temperature (about 90 bar and 740 K). Interestingly, recent Venus orbiters provided exciting clues about the variabilities of Venus’s atmosphere across the globe and over time. To find mechanisms behind the reported variabilities, more observations are needed. Better understanding of the current status of the planet may be the key to discovering its past. In this seminar, I would like to introduce how our knowledge of Venus has been shaped by observations.