About 310 million years ago, the area that is now Illinois was covered by shallow coastal waters and muddy shores. Sediment from rivers often buried marine creatures, and in some cases trapped them in iron-rich nodules before they could decay. That is how soft-bodied animals, which usually do not leave fossils, were preserved in detail at a site known as Mazon Creek.
Every known fossil of the Tully monster comes from this one location. It is possible the animals were widespread across the prehistoric world, but this may be the only place where the chemistry preserved their bodies.
The creature was named after Francis Tully, an Illinois fossil collector who first found it and brought it to scientists. It was not large, usually measuring about 3 to 14 inches long. It had a soft, worm-like body without shells or bones. Its most unusual feature was a long, flexible snout ending in something resembling a claw, which it likely used to reach out and pull in food. Its eyes sat on a stiff horizontal bar extending from its head, giving it a wide field of view.
Scientists still disagree on how to classify the Tully monster. One group holds that a pale stripe down the middle of its body was a gut line, placing it among invertebrates. Another argues it was a notochord, a primitive stiffening rod, which would make it a vertebrate and a distant relative of fish. The animal was probably a slow swimmer that drifted through the water and used its snout to search the mud for jellyfish, sea cucumbers, or decaying matter.
The Tully monster disappeared long before the extinction events that wiped out the dinosaurs. There is no evidence of an asteroid or volcanic eruption. It likely vanished because its habitat changed as the climate shifted and tropical estuaries dried up. The creature left no known descendants, and nothing alive today resembles it. Scientists have more than 2,000 fossils, but no living counterpart to compare them to.
Other prehistoric animals were equally unusual. Hallucigenia, a tiny worm-like creature, was initially reconstructed upside down. Scientists originally thought its long spines were legs and its soft protrusions were tentacles, but better fossils showed the opposite: the spines were defensive, and the soft parts were legs. Opabinia, a shrimp-like animal with five eyes and a flexible nozzle, was met with laughter when first presented at a science conference in the 1970s. Helicoprion, a shark-like fish, had a spiral of teeth in its lower jaw that scientists spent decades trying to place correctly before realizing it was inside the mouth.
Antarctica has also produced a range of fossil discoveries. A giant soft-shell egg roughly 11 inches long and 7 inches wide, dating to about 66 million years ago, was found in Antarctica and later identified in Chile. It is the largest soft-shell egg ever found and the second largest egg of any known animal. Researchers believe a marine reptile such as a mosasaur laid it, though this cannot be confirmed.
In 2025, a large iceberg named A-84 broke away from the George VI Ice Shelf in Antarctica. Shortly afterward, researchers aboard the ship Falkor 2 explored the newly exposed seafloor in the Bellingshausen Sea. Using an underwater robot, they spent eight days surveying depths of more than 4,200 feet. They found a rich ecosystem with corals, sponges, anemones, sea spiders, icefish, octopuses, and a species of phantom jellyfish. Some of the animals may be new to science. The presence of large, slow-growing sponges suggested the community had been established there for a long time, sustained by underwater currents carrying nutrients beneath the ice.
Satellites have also helped scientists identify subglacial lakes in Antarctica. Data from ICESat, CryoSat-2, and ICESat-2 allowed researchers to spot two new lakes near a pair of larger ones. These lakes are part of a network of meltwater that fills and drains continuously through waterways beneath the ice, causing the surface above to rise and fall. The drainage of one lake released as much as 198 billion gallons into the ocean in three days. Scientists are studying how this system affects the speed of the Antarctic ice sheet, sea level rise, and marine ecosystems. Water samples from one lake contained about 10,000 bacterial cells per milliliter, indicating that microbial life can persist in these extreme conditions. The findings may also inform the search for life on other planets, such as Mars.
Antarctica itself is the fifth largest continent, about twice the size of Australia, and holds roughly 70 percent of the world’s fresh water. It is the driest, coldest, and windiest continent, with coastal regions occasionally reaching 50 degrees Fahrenheit. The lowest recorded temperature was about minus 135 degrees Fahrenheit. During summer, the ice surface covers about 1.2 million square miles; in winter it grows to about 7.3 million square miles. There is no native human population, and no single country owns the continent. About 5,000 people reside there in summer at research stations, dropping to around 1,000 in winter.
The McMurdo Dry Valleys are among the driest places on Earth, with little precipitation and winds that can reach 200 mph. The conditions there are similar in some respects to the surface of Mars, and scientists use the region to study how life might survive on other planets.
Blood Falls, a five-story waterfall in the McMurdo Dry Valleys, appears red because ancient saltwater rich in iron flows through a crack in a glacier and rusts when it meets air. The water originally came from a lake that became sealed off by glacial ice, and it now sits more than 1,300 feet below the surface.
Google Earth users have occasionally reported unusual shapes in Antarctica, including a doorway-like formation, a large object resembling a ship, and a pyramid-shaped peak. Scientists have explained these as natural features. The doorway is a grounded iceberg or rocky ridge shaped by wind and melting ice. The ship-like object was likely pareidolia, a tendency to see familiar shapes in random patterns, and had melted away by the time it was revisited. The pyramid is a mountain peak known as a nunatak, part of the Ellsworth Mountains.
In 2017, researchers found DNA traces of algae, moss, and possibly small animals in subglacial caves warmed by volcanic activity. Mount Erebus, the southernmost active volcano, contains cave systems warm enough for t-shirts. Scientists have also found a hidden underground river beneath the Ross Ice Shelf, where a camera lowered through a drilled hole revealed hundreds of amphipods, small shrimp-like creatures.
Researchers studying Lake Enigma, a frozen lake in Antarctica, discovered a layer of liquid water about 40 feet deep beneath the ice. The water contained microbial mats, and some of the microbes were capable of photosynthesis. The lake may resemble environments on icy moons such as Europa or Enceladus.
Tiny pieces of amber found in Antarctic mudstone provide evidence that resin-producing trees once grew there during the mid-Cretaceous period. The trees would have had to survive months of darkness during the Antarctic winter, likely by going dormant.
Satellite images have also revealed four new colonies of emperor penguins. Three of the colonies are small, with fewer than a thousand breeding penguins each. One colony was found near the Lazarev Ice Shelf, where a larger colony was thought to have disappeared in 2019; it appears the penguins relocated due to changing sea ice conditions.
Fossil evidence suggests a giant river system flowed through Antarctica about 40 million years ago. Researchers found sediment patterns similar to modern river deltas, and the river likely began in the Transantarctic Mountains and traveled about 930 miles before reaching the sea.
The first undisputed landing on Antarctica occurred on January 24, 1895, at Cape Adare, during a whaling voyage led by Henrik Bull. The continent had been sighted earlier, in January 1820, during an expedition commanded by Fabian Gottlieb von Bellingshausen. Ancient Greek philosophers had speculated about a southern land, referring to it as Antarktos, meaning opposite the bear, in reference to the northern constellations.
Antarctica has no official time zone. All lines of longitude meet at the South Pole, so researchers typically keep the time zone of the country they came from.
The continent is home to five species of penguins, along with seals and whales. Emperor penguins are the largest penguin species and can dive more than 1,800 feet deep and hold their breath for over 20 minutes. Ancient penguin fossils from around 38 million years ago show individuals the size of humans.
One long-running mystery involved a strange sound recorded in Antarctic waters starting in 1960, named bio-duck. The source was unknown for decades. Researchers eventually determined it was the call of minke whales. A similar sound near Australia and New Zealand, named bio-goose, likely came from other whales or young minke whales.
In the Mariana Trench, scientists recorded a low rumble followed by a metallic ping, named bio-twang. They identified it as the call of Bryde’s whales. A different sound, known as the Bloop, was recorded near Point Nemo in 1997 and initially sparked speculation about a sea monster. It was later identified as the sound of an iceberg cracking and collapsing.
An unexplained sound known as Upsweep, a series of ascending tones repeated at intervals, was first detected in 1991 in the Pacific Ocean. Its source has not been identified, though scientists have considered volcanic activity, earthquakes, and marine animals without conclusive results.
In 2019, researchers discovered a fossilized prehistoric marine reptile in Antarctica that resembled descriptions of the Loch Ness Monster. The animal, which lived about 70 million years ago, could reach 36 feet long and weighed roughly 15 tons, about the size of three elephants.
Other notable fossil finds include Kumimanu fordycei, a penguin that lived in New Zealand about 55 million years ago and weighed over 330 pounds, and the tiny great ape Burmanfried schmitzi, which lived in Germany about 12 million years ago and weighed about 22 pounds.
Recent discoveries of new living species include an electric blue tarantula from Thailand, a ghost shark found at around 2,000 feet deep in the Andaman Sea, a giant crocodile-like amphibian from Brazil that lived over 240 million years ago, and a dwarf deer in Peru about the size of a basset hound. A new species of pacu with human-like teeth was named Myloplus sauron after the Lord of the Rings villain because of a bold vertical mark on its side. A spider was named Venomia tomhardyi after actor Tom Hardy due to black spots on its abdomen resembling the Marvel character Venom. Harrison Ford and rapper Prince Ea have also had new species named after them.
The Kerguelen Plateau, a largely submerged volcanic landmass in the southern Indian Ocean, is considered a microcontinent. It formed about 130 million years ago as the supercontinent Gondwana broke apart, built up by volcanic activity from the Kerguelen Hotspot. At its peak, the lava flow may have been substantial enough to fill tens of thousands of Olympic-size swimming pools each year. Over the last 20 million years, the plateau has sunk, and only the Kerguelen Islands and the McDonald Islands remain above water.
The Gamburtsev Subglacial Mountains in Antarctica are buried under ice and were discovered in 1958 using seismological instruments. Researchers believe they formed about 650 million years ago during the assembly of Gondwana and once reached heights similar to the Himalayas. Because they have been protected by ice, they are among the best-preserved ancient mountain belts on the planet. Scientists determined their age by studying tiny zircon crystals in rock samples, using the ratio of uranium to lead to calculate when the rock formed.
An ancient landscape beneath the ice in East Antarctica has remained largely unchanged for about 34 million years. In areas where the ice is thick and stable, it has acted as a protective layer, preventing erosion from wind, water, or other natural forces. The traces of rivers, valleys, and land blocks from the time before the continent froze are still visible under the ice.
