Australia and Antarctica are the only two continents that are located entirely below the equator. Several continents straddle the equator, however, including South America, Africa and Asia. Researchers believe that a subcontinent called Zealandia, which broke from Australia and Antarctica, also exists below the equator. A continental shelf below the surface of the ocean matches up to Australia.
The equator represents zero degrees latitude and divides the earth into the northern and southern hemispheres. It is also the widest part of the Earth. At the equator, the Earth's circumference is just under 25,000 miles, and the Earth's revolution speed is greatest at the equator. Gravitational pull, however, is slightly less at the equator than it is on other points of the earth. Twice a year, the sun rises directly over the equator, which determines the changing of the seasons. Regions located below the equator are typically tropical with hot, humid climates, temperatures that vary very little and a definitive wet season. Antarctica is cold due to its extremely limited exposure to the sun. Other areas near or below the equator with high elevations also experience cool or cold temperatures. Many of the Earth's species of flora and fauna are located in the rain forests below the equator.