The passage of Venus in front of the Sun is among the rarest of astronomical events. Only six transits are known to have been observed by humans before: 1639, 1761, 1874, 1882 and 2004. The next event will occur in 2114.
When Venus is in transit across the Sun, the planet appears as a distinct round black spot with a diameter of just 1/32nd of the Sun. The size is large enough to be perceived with the naked eye.
However, take special precautions when attempting to view the silhouette of Venus against the bright Sun. Below is a link to purchase inexpensive glasses to watch the event which will protect your eyes.
The beginning of the transit will be visible from all of North America, Greenland, extreme northern and western portions of South America, Hawaii, northern and eastern portions of Asia including Japan, New Guinea, northern and eastern portions of Australia, and New Zealand. The end will be visible over Alaska, all of Asia and Indonesia, Australia, Eastern Europe, the eastern third of Africa, and the island nation of Madagascar.