The oldest and largest meteorite impact site (astrobleme) in the world is the Vredefort Dome. Around two billion million years ago, a meteorite larger than Table Mountain slammed into the planet near present-day Vredefort. The Vredefort Dome in the Northern Free State of South Africa is a UNESCO World Heritage Site. The town most usually linked with the Vredefort Dome, the largest impact crater still visible on Earth, is Parys, located on the banks of the Vaal River, which originates on the Highveld and passes through the dome region. The 'crater' region is little over two billion millions of years old, but the rings of what was once molten rock are still visible in photographs from orbit. The actual crater (with an estimated initial diameter of roughly 300 km) has long since eroded, but this erosion has exposed a half circle of enormous upturned boulders (often referred to as the 'Bergland') with a diameter of approximately 45 km. The meteorite's impact drove this material up from the Earth's mantle. Experts estimate that it was at least 10 kilometers wide.
In 2005, the Vredefort Dome was designated a UNESCO World Heritage Site, making it one of South Africa's eight World Heritage sites. It is the largest and oldest known impact relic from a time when life on Earth consisted of basic algae, and many scientists believe that the meteorite that struck what is now Vredefort may have played a key role in the evolution of life on Earth.
Other intriguing characteristics of the Vredefort Dome include magnetic fields that interfere with the working of compasses and a belief that the 'hole' in the earth was not produced by a meteorite but rather by a burst from within the globe.
Visit the information center in Venterskroon or the Parys Museum to learn more about the dome and examine rock samples. Even if you have no interest in geology, there are several activities in and around Parys and Vredefort that make use of the local geology. These activities include river rafting on the Vaal River, trail running, mountain biking, horse trails, guided geology and dome tours, quad-biking, abseiling, and hiking. As a destination for outdoor and family adventure, team-building, and group adventure activities, the list is virtually infinite.
Article Courtesy of www.sahistory.org.za/place/vredefort-dome-free-state-north-west