The world's strangest river emerges in Antarctica for just a few months each year.

Antarctica contains a vast amount of water, most of which is frozen, leading some to believe that there are no rivers on the icy continent; however, this is not entirely accurate. In fact, Antarctica is home to a number of rivers and waterways, the longest of which is the Onyx River, as reported by IFLScience.

Technically, the Onyx River is a stream of meltwater, measuring 32 kilometers in length. This may seem insignificant compared to the Nile's length of 6,650 kilometers, but considering the icy landscape it traverses, it is quite impressive.

It is known that the river originates in the McMurdo Dry Valleys of Antarctica and flows westward from the terminus of the lower Wright Glacier into Lake Vanda — in simple terms, it does not flow into the ocean, but rather away from it.

Researchers believe that the river is an example of a closed drainage system, where water systems do not flow into the sea, a phenomenon caused by geological quirks. Glaciers block the entrance to the Wright Valley, meaning that the Onyx has no choice but to flow inland toward the ice-covered Lake Vanda.

It is known that there are nine such meltwater streams in Antarctica, but they differ slightly from most other rivers. For instance, the Amazon and Congo begin at mountain sources and eventually form rivers, whereas the Onyx flows when the Lower Wright Glacier melts. As a result, the flow is semi-permanent — it only forms in the summer when temperatures are high enough to melt the ice.

Rain does not contribute to the runoff, as it is very rare in the Dry Valleys, and any precipitation that occurs sublimates before reaching the river. At the same time, the melting glacier typically provides enough water to sustain the river's flow — in recent decades, there have been several floods during particularly warm summer seasons, and in 1984, a team of scientists from New Zealand even managed to raft down the Onyx River.

Climate change has also impacted the Onyx River — scientists have found that as temperatures rise due to climate change, the flow season of the Onyx is shifting earlier and becoming longer. However, the volume of water flowing through the stream is believed by scientists to be decreasing.

Researchers note that the Onyx River is not only the largest of the meltwater streams in Antarctica but also the most ecologically significant. The river has its own mini-ecosystem and supports a diverse microscopic life, from tardigrades and nematodes to cyanobacteria and phytoplankton. Studies also show that algae flourish in the river's waters, but scientists note that we are unlikely to ever find fish in them.