Aliens in the shape of unclassifiable mushroom-shaped creatures have been discovered in the ocean depths off Australia.
Two species of the strange organisms were found that could not be placed in any existing phyla, the large families of living things that include vertebrates and flowering plants.
The animals, known as Dendrogramma, consist mainly of an outer skin and inner stomach separated by a dense layer of jelly-like material. Words: PA
Scientists suspect they are related to ancient extinct life forms that lived 600 million years ago and may have represented a failed early attempt at multicellular life.
They were discovered in a collection of organisms dredged up in 1986 from depths of 400 and 1,000 metres (1,312 and 3,280 feet) on the south-east Australian continental slope.
Researchers have only now isolated the two species of Dendrogramma described in the latest edition of the online journal Public Library of Science ONE.
The species have been named Dendrogramma enigmatica and Dendrogramma discoides.
Danish lead scientist Dr Jorgen Oleson, from the University of Copenhagen, said: "New mushroom-shaped animals from the deep sea have been discovered which could not be placed in any recognised group of animals.
"Two species are recognised and current evidence suggest that they represent an early branch on the tree of life, with similarities to the 600 million-year-old extinct Ediacara fauna."
A new attempt may now be made to find other specimens of the mushroom animals.
World's strangest animals
'Alien' mushroom creatures discovered in ocean off Australia
Where can I find one? These endangered nocturnal primates are typcially found in the eastern rainforests of Madagascar. They're also known to hang out on the island of Nosy Mangabe, on the country's eastern coast.
Tell me a secret: According to legend, the aye-aye is an evil omen. It's so feared by the people of Madagascar that it is still often killed on sight.
Where can I find one?Alpaca are kept in herds for their wool on the level heights of the Andes of southern Peru, northern Bolivia, Ecuador and northern Chile.
Tell me a secret: Alpaca spit at each other (and humans) when they're cross.
Where can I see one? Sometimes referred to as a sea cow, the dugong lives in the shallow coastal waters of northern Australia, where they can live for up to 70 years.
Tell me a secret: Although an acquatic mammal, the dugong is actually more closely related to the elephant than the whale or dolphin.
Where can I find one? This primate lives in southwest Amazon Basin, north Bolivia, west Brazil and Peru.
Tell me a secret: The emperor tamarin allegedly got its name because of its similarity in appearance to the German emperor, Wilhelm II.
Where can I find one? The flightless kiwi bird can only be found in New Zealand. It's semi-nocturnal and very shy - so very few New Zealanders have seen their national bird in the wild.
Tell me a secret: Despite its awkward appearance, a kiwi can outrun a human.
Where can I find one? The probiscis monkey is found exclusively on the island of Borneo in south east Asia, primarily in mango swamps. Their long noses are thought to attract females.
Tell me a secret: The probiscis monkey is an expert swimmer and has the longest nose out of all primates.
Where can I find one? Along the southern and western coasts of Australia. Leafy sea dragons have become endangered through pollution and are now a protected species.
Tell me a secret: Because of their excellent camouflage, leafy sea dragons don't have any natural predators.
Where can I find one? These strange-looking animals remain furless all their lives and live in parts of Sub-Saharan Africa. They are virtually blind but have acute hearing.
Strange fact: Naked mole rats live in colonies led by one dominant rat (the queen). Like some insect species, the queen is the only naked mole rat female to breed and bear young.
Where can I find one? The platypus is unique to Australia, inhabiting fresh water streams, rivers, lakes and farm dams.
Tell me a secret: The male platypus has a venomous spur on the inside of each hind claw. The poison can kill a dingo and is said to be leave humans helpless for several weeks.
Where can I find one? The soft-shelled turtle can be found in the waters of China and south east Asia as well as Russia.
Tell me a secret: Using its long nostils, the Chinese soft-shelled turtle can snorkel in shallow water using its long nostrils.
These bugs have extremely long and powerful legs that make them look like they are doing wacky dance moves. Native to Peru, the insects resemble stick insects but have distinctly horse-shaped faces - hence their names...
Where can I find one? The largest and heaviest lizards on earth, komodos are also the most lethal. They're native to Indonesia, and will eat anything, including deer, pigs, water buffalo and even humans. Their saliva teems with bacteria, so within 24 hours of being licked or bitten, most animals will die of blood poisoning. They are classified as an endangered species and protected under Indonesian law.
Tell me a secret: Komodo dragons have lived for millions of years, but were only discovered by humans 100 years ago.
Where can I see one? One of the world's smallest primates, the tarsier lives in the forests of Sumatra, Borneo and the Philippines.
Tell me a secret: Tarsiers have the biggest eyes of any land mammal. In fact, their eyes are so large that they'd be the equivalent to the size of a grapefruit in a human being.
Where can I see one? These nocturnal creatures are Australian egg-laying mammals who live in rainforests and deserts.
Tell me a secret: An echidna can lift an object twice its weight.
Where can I see one? You'll have to dive pretty deep - they inhabit the extreme depths off the coasts of Australia and Tasmania as well as Japan - but even if you did that you'd be very unlikely to see one as they're pretty rare, thanks to overfishing.
Tell me a secret: The blobfish has no muscles - it floats above the sea bed as a gelatinous mass.
Where can I see one? These distinctive tentacled underground mammals are native to north America.
Tell me a secret: Star-nosed moles have 22 tentacles with more than 25,000 receptive organs - all in a space smaller than one square centimetre.
'Alien' mushroom creatures discovered in ocean off Australia
Visit the mysterious island of Socotra and you'd be forgiven for thinking you were on another planet. Part of a group of islands off the African coast, this place teems with more than 800 rare species of flora and fauna, many of which can't be found anywhere else on earth.
Want to go there? The best time for wildlife enthusiasts to visit is between January and May. Flights run from Sana'a Airport, the capital of Yemen. There is a growing offering of tourist accommodation. Visit Socotra Eco Tours for more.
This incredible rock formation is the result of hundreds of millions of years of erosion: the stripes are caused by leaking minerals in the rock.
Want to go there? Simple! You just need to drive four hours east from Perth...
This huge hole in the sea off the coast of Belize is so large and deeply blue that it's visible from space. It's believed to have formed after the Ice Age, when ice melted into the sea, covering a giant collection of caves. It's a popular spot with divers as it brims with aquatic life.
Want to go there? Take a 75-minute ferry trip from Belize city or a 20-minute flight to San Pedro.
These ancient rock formations on the Otago coast of New Zealand are believed to date back more than 60 million years. The largest boulders weigh seven tonnes. Mauri ledgend tells that the boulders are remains of eel baskets, while locals call them "giants' gobstoppers".
Want to go there? Have a look at our guide to New Zealand for more information.
Nestled in the heart of Cappadocia in central Antolia, this eerie national park is composed of strange rocks shaped over centuries out of eroded volcanic stone.
Want to go there? The park can be reached on foot from Goreme village, where there is a plethora of hotels and pensions. Best time to visit is March til November.
These 'elephants' are part of train of gigantic pink granite boulders perched on a hill These curious geologic formations were formed 1.5billion years ago out of magma being pushed to the surface.
I want to go there! Drive or book a coach tour from Las Vegas to the Valley of Fire.
Fancy an egg cooked on 'Sulfur Mountain'? The vents on this volcano are permanently steaming and smoking, and vendors sell eggs that have been cooked by the natural heat.
Want to go there? Iozan is part of Akan National Park, just outside the hot spring resort of Kawayu Onsen. Main gateways to the park are Kitami and Bihoro in the north, and Kushriro in the south.
This fairytale-like cascade of thermal spring waters is a unique natural site considered by many to have healing properties (the waters have been used since Roman times). The springs are laden with calcerous salts which have created plateaus, stalactites and basins to form Pummukkale, which literally means "Cotton Castle".
Want to go there? The springs are about 30km from Bodrum by car, or you can book a day trip from the city. If you want to stay, there are limited options, but the nearby town of Denizli is a safer bet for accommodation.
Green Sand Beach, or Papakolea, is one of only two green sand beaches in the world. Sitting on the sotuthern tip of Hawaii's Big Island, the sand is a distinctive olive green colour caused by a now extinct volcano.
Want to go there? Green Sand Beach is pretty isolated - you'll need to take a three hour drive from the nearest resort along the Kohola Coast.
Huge craters, steaming ground, sinister rock formations, hot water springs and lime green water: the Devil's Bath has to be seen to be believed. Wai-O-Tapu Thermal Wonderland, Rotorua is New Zealand's most diverse geothermal area.
Want to go there? Rotorua is a three-hour drive from Auckland and is well served by hotels and visitor centres. Visit RotoruaNZ for more.
Thousands of delicately carved spires rise in brilliant colour from the rock amphitheatres, created by millions of years of wind, water and geologic mayhem.
Want to go there? Take a day tour from Las Vegas or spend some quality time and stay overnight in one of the many lodges nearby.
What makes these volcanic lakes so special? Well, they actually change colour from green to blue, red and black. The locals believe that The Lake of Old People, Lake of Young Men and Maidens and The Enchanted Lake are the spiritual resting place of their ancestors and change colour depending on the moods of the spirits. Don't be tempted to get too c lose though, in 1995 a Dutch tourist fell into one of the lakes and his body was never recovered.
Want to visit here? Kelimutu is in the centre of Flores and tourists start their trek from the small village of Moni, nine miles from the lakes.
Mount Roraima has sheer, plummeting, 400-meter high cliffs and is bordered by three different countries - Venezuela, Brazil and Guyana. It sits in Guyana's Highland Range, some of the oldest geological formations known to man and is home to its own ecosystem, the world's highest waterfalls and unique wildlife like the carnivorous pitcher plant.
Want to visit here? The cliff walls can only be tackled by experienced climbers but there is a hiking path that occurs naturally in the mountainside. See explore.co.uk for holiday ideas.
An hour from Senegal's capital is Lake Retba, a vividly pink lake surrounded by sand dunes. The lake has a salt content similar to the Dead Sea and its distinctive colour comes from the Dunaliella salina algae. Not much lives in the lake and locals use it to mine salt and promote tourism in the area.
When to go: The lake is pinkest during the dry season from November to June.
Deweze, or The Door to Hell, as it is more commonly known, is found in the middle of the Karakum Desert. It was discovered in 1971 when Soviet geologists drilled into a cavern filled with natural gas. The ground collapsed revealing a huge hole filled with poisonous gases. To avoid the discharge they decided to try and burn the gasses away and it's still burning today.