When Venus comes directly between the Earth and the Sun, it is called a transit. During the transit, the planet Venus blocks out a portion of the Sun's image, appearing as a black dot on the face of the Sun. Over time, the black dot travels across the face of the Sun (transits), and exits out another edge. The last time this happened was June 5, 2012; information as to how it could have been seen is provided. A NASA map of the transit is provided.