Swimming in an open sea or hiking in a deep forest on a vacation can be fun and exciting especially when you have a chance to visit Australia. Australia is home to vast biodiversity. It is a unique country for those who want adventure and to encounter different cultures, traditions, and of course, animals. About six million visitors come to Australia each year because of its beautiful beaches, unique flora and fauna, friendly and hospitable people, and relaxed atmosphere. Australia has some 9,700 protected nature areas such as national parks and can offer visitors a varried and diverse array of nature-based tourism opportunities. This country is home to more than one million species of plants and animals, many of which are unique. Australia is a “megadiverse” country, and is one of the most biologically rich countries in the world. There are 17 megadiverse countries, comprising a mere 10 percent of the earth's surface, but together accounting for more than 70 percent of its biodiversity. Australian biodiversity has been influenced by the range of environmental conditions in the country. Australia has diverse bodies of water and land which are home to a wide range of species of animals you can only find in the country. One of those is the Australian box jellyfish. The Australian box jellyfish is considered the most venomous marine animal and despite their gentle physical characteristics, they are considered one of the most dangerous species of jellyfishes. Box jellyfish are identified and distinguished by their box-like body. Some species of box jellyfish like the one in Australia produce potent venom delivered by contact with their long tentacles. Unlike other stings from other species, their venom can be fatal to humans. Its name was obviously derived from its physical characteristics and unlike other species, with the help of their form, box jellyfish can move more rapidly. They can swim up to a speed of  6 meters per minute. Its bell or head usually reaches about 6.3 inches (16 cm) in diameter but can grow up to 13.8 inches (35 cm). From each of the four corners of the bell trails a cluster of approximately 15 tentacles where venom can be found. The pale blue bell has faint markings or patterns when viewed from certain angles. If you look closely at its head, you’ll notice its resemblance to a human head or skull which makes it look scarier. Due to its almost transparent color, the creature is nearly impossible to notice in its habitat which makes it more dangerous as you cannot easily avoid contact. When the jellyfish are swimming or floating on the water, their tentacles contract so they are only about 6 inches (15 cm) long and only about 0.2 inches (5 mm) in diameter. But when they are hunting, their tentacles become thinner and extend up to about 10 feet (3 m) long. Their tentacles are covered with a high concentration of stinging cells called cnidocytes, also known as stinging cells. They are specialized cells that contain an “explosive” organelle called cnidocyst that acts as a 600 million-year-old microscopic injection system and is important for prey capture and anti-predator defense. Common to species in the diverse phylum Cnidaria, these cells can launch a toxic barb or blob to enable cnidarians to stun prey or deter invaders. Box jellyfish are active hunters during the day time; while at night, they are seen resting on the ocean floor. Australian box jellyfish have four eye-clusters with 24 eyes. Some of these eyes are quite sophisticate. They have a lens and cornea, and an iris that can contract in bright light, and a retina. Their speed and vision lead some researchers to believe that box jellyfish actively hunt their prey, mainly shrimp and small fish. Although all box jellyfish contain venom and are considered terrors of the sea, they are not dangerous to consume for some marine predators like green sea turtles which are the main predators of box jellyfish. Aside from green sea turtles, other predators are ocean sunfish, gray triggerfish, seabirds, whale sharks, some crabs, and some whales such as humpbacks. They are attracted to light of different colors but blue light seems to elicit a feeding behavior. Interestingly, black objects seem to cause them to move away. They can actually see images, with the aid of light-focusing lenses. A researcher named Anders Garm from the University of Copenhagen has found that the jellyfish always keeps its upper lens eyes pointing towards the sky. They live on a diet of prawns and small fish and are prey to turtles, whose thick skin is impenetrable to the cnidocytes of the jellyfish. Box jellyfish have tentacles covered in biological booby traps known as nematocysts - tiny darts loaded with poison. People and animals injected with this poison may experience symptoms such as paralysis, cardiac arrest, and even death, all within a few minutes of being stung. Although jellyfish can be found in many seas and oceans, box jellyfish can be commonly found in the tropical Indo-Pacific region, the Atlantic Ocean, and the East Pacific Ocean. Some species were recorded to be habituating seas in North California, the Mediterranean Sea, and Japan. In the wild, the box jellyfish will live up to three months but can survive up to seven or eight months in a science lab tank. Studying with different poisonous animals, Hugo Flecker, an Australian medical practitioner, radiotherapist, toxicologist, and natural historian, was concerned at the unexplained deaths of swimmers. He identified the cause of death of a 5-year-old boy after being stung in shallow water at Cardwell as the box jellyfish later named Chironex fleckeri. As he pursued his studies, in 1945, he described another jellyfish envenoming which he named the "Irukandji Syndrome", later identified as caused by the box jellyfish Carukia barnesi. In Australia, critical encounters are most often caused by the largest species of this class of jellyfish, which is one of the world's most venomous creatures. The Australian box jelly, is considered as the largest of the cubozoans. They have caused at least 79 deaths in Australia alone since the first report in 1883. Certain box jellyfish stings can kill a person within minutes while other box jellyfish stings can lead to death in 4 to 48 hours after a sting due to a delayed reaction to the sting. A single box jellyfish creates and contains enough venom to kill more than 60 humans. To a human, a sting will cause necrosis of the skin, excruciating pain and, can even cause cardiac arrest and death within minutes, if the sting is severe enough. The venom of a box jellyfish is not the same as other stingers. It’s a complex concoction of different compounds, none of which are very well understood to this day. Scientists know it contains a multitude of compounds that, when injected together, work very effectively to immobilize and kill their victims. For humans, it can cause permanent scarring of the skin, destroy blood vessels and produce intense muscle spasms that are so severe that muscles of the heart can’t relax between contractions, stopping blood flow. A potent venom is composed of many different components and each acts on a different part of the human body. One component causes localized pain while the other component travels through veins and arteries straight to the heart which usually causes heart failure. After a sting, the pain comes on quickly and continues to get more intense and widespread through the body causing unbearable pain. Australian waters are home to different types of marine life and encounters with box jellyfish and crocodiles are common. To avoid such a painful, and possible deadly encounter, always wear appropriate protective clothing or swim gear. Lycra suits will reduce risk while swimming, especially in the summer months when they are actively hunting at day time. Only swim on patrolled beaches, preferably in netted swimming areas with lifeguards. It’s advisable not to a