Update: On June 5 and 6, weather and location permitting, citizens of Earth were able to see a solar event that won't be repeated until 2117 - the transit of Venus. Similar to an eclipse, a transit occurs when a planet or other object moves between the sun and Earth.
Here, the transit of Venus has almost begun.
Venus appears to be a spot on the sun as it appears to fly over the sun's surface in this image taken by NASA's Solar Dynamics Observatory (SDO).
How the Venus transit might look to a normal observer from Earth using a filter.
This image was taken by NASA Astronaut Don Pettit from aboard the International Space Station on June 5, 2012.
Credit: Don Pettit
SDO shows the path of Venus across the sun.
Venus transits usually occur in pairs, once per century. This 2004 photo catches a plane that appears to be streaking toward Venus.
NOTE: If you want to see the transit - DO NOT STARE at the sun. Use some kind of eye protection such as welder's glasses. Here are some eye safety techniques.
Here's a real photo of the sun with the most likely route of Venus as it transits.
This is a photo of Venus approaching the blocked out sun.
Photos taken by the TRACE satellite.
This image shows where Venus was seen in 2004 and where it will be seen on June 5 and 6, 2012.
The transit will be captured by numerous photos and videos, of course. Some of the most interesting will come from the International Space Station and the Hubble Space Telescope. The Hubble's lens cannot tolerate the brightness of the sun so scientists plan on it capturing reflections off the moon.
This rocky location on the moon is where scientist plan to have the Hubble focus on.
This view of the 2004 transit of Venus was taken from the International Space Station
Credit: Thomas Maruska