Hey everyone and welcome to another episode of CNN 10. I'm Mina Derson filling in for Koi Wire from CNN New York and I am so excited to be here. Today is Wednesday, January 21st. Now let's get you your news. We're going to start in Australia where a series of shark attacks has forced dozens of beaches to close and triggered warnings to stay out of the water. Four attacks were reported in the span of just 2 days at popular beaches in the state of New South Wales, which is on the country's eastern coast. The attacks have all been attributed to bull sharks, a species with the unique ability to live in both salt and freshwater. Bull sharks commonly hunt near rivermouths and other murky bodies of water like Sydney Harbor, which is where one of the attacks occurred. CNN's Angus Young has more on why experts are worried that recent weather trends in the region may fuel more encounters. >> The family of a 12-year-old Australian boy is fearing the worst after he was attacked by a shark at a popular Sydney harour beach. Niko Antich has been hospitalized since Sunday when he became the first victim in a rare spate of shark attacks. Rangers have been scouring this area of Sydney Harour since Sunday night looking for a shark that attacked a boy here. That boy is now in a critical condition in hospital, only alive because one of his friends jumped into the water to save him. Four shark attacks in 48 hours. three in Sydney, another on the coast to the north. All were attributed to bull sharks, a stocky species with powerful jaws that lurk in murky waters. >> When there's certain types of events like very heavy rainfall, we know that bull sharks, which are tolerant of fresh water, move around the harbor quite actively to move to where the fish are being pushed by the changes in salinity from the freshwater inputs. A 25-year-old surfer is also in a critical condition after he was attacked on Monday at a beach in Manley, another Sydney hot spot. >> At the moment, there's just been more sharks up and down the eastern coast of Australia than anyone's ever seen. Just it it's actually it's actually radical. So, I don't really want to go out for a while. >> An 11year-old boy with a close call at nearby Dy Beach. These bites taken from his surfboard. He got away unheard. The attacks are not the first in Sydney in recent months. Here, temperatures are expected to surge ahead of an upcoming holiday weekend. Many will be judging whether to risk a swim. >> And it's time for 10 trivia. What is the highest posted speed limit in the United States? 70 mph, 85, 90, or 100? The answer here is 85 mph. And those signs are posted in Texas, the highest posted in the world. That would be in Abu Dhabi at about 99 mph. Rome, Italy, has become the latest European capital to reduce its speed limit. The move aims to tackle pollution and obiate the number of accidents in a city where streets are packed with cars and tourists. CNN's Barbie Latin Adau has the details. The streets of Rome can feel like an obstacle course, a chaotic mix of cars, scooters, and pedestrians buzzing through the city's ancient narrow streets. But Rome is trying to curb the whirlwind pace of some of its drivers, cutting the speed limit in the historic center almost in half from 50 to 30 km per hour. The slowdown is an effort to reduce accidents and pollution and it's dividing opinions in the eternal city. >> In my opinion, it is wrong. 30 km hour is too little. 50 was fine. >> Some people drive extremely fast. I ride a scooter and often risk being hit. For pedestrians and bicycles safety, too, it's better to go slowly. And just as Rome wasn't built in a day, the city's transport chief says drivers have about a month to gear down. With the new rules gradually being enforced over the next 30 days, other cities like London, Brussels, and Paris have imposed similar speed limits. Officials in the northern Italian city of Bolognia say a similar measure reduced road accidents by 13% and fatalities by 50% in the year after it was enacted. And besides the expectation of saving lives, local authorities say the lower speed limit is also expected to reduce noise levels in the city center by around 2 dB. A lot to gain by slowing down. Though some people say the need for speed could be a hard habit to break. Now to a behavioral breakthrough that has researchers saying, "Holy cow." Meet Veronica, a pet cow in Austria with a unique skill. The clever cow has learned to use sticks and other tools to scratch parts of her body she can't otherwise reach. Her owner says she's been doing it for a decade. But when researchers at a nearby university saw a video of Veronica in action, they knew they had to study her. Turns out the backscratching bovine not only uses tools like brooms intentionally to get the itch, she even prefers different ends for specific parts of her body. It's the first time this behavior has been documented in a cow. And the team of experts says it could be evidence that cows possess much higher cognitive capabilities than previously thought. They say Veronica's special skill may even qualify as multi-purpose tool use, a rare feat that's only been documented otherwise in chimpanzees. And it may still be winter in the Eastern Hemisphere, but over in the Netherlands, spring is already making a guest appearance. Look at this early burst of color taking over Amsterdam. As thousands celebrated National Tulip Day, growers turned this square into a free pick your own garden, giving away 200,000 tulips to kick off the selling season. >> We compare uh the flowers, they are in a very excellent condition this year. Uh also a little bit more better than last year. >> The Netherlands is the world's largest producer of cut tulips, and events like this signal the start of a busy season ahead. Visitors were allowed to pick up to 10 tulips each and for some it was a first time experience. >> We are happy to see tulips. It's our first time. It's my first time seeing tulips and it's like a big cultural exchange for me. >> I just love flowers and it's my first time for me being here and uh nobody's buying me flowers at the moment. So yeah, I think it's a jackpot for me. Now to a new record for one of the world's most famous puzzles. Meet 95-year-old Frank Zaminsky, who's now broken three world records with a Rubik's Cube. Turns out Frank has loved cubing since the 70s. So, he recently joined a local club in upstate New York with school kids. They encouraged him to enter a contest this past Sunday where he set a World Cube Association record in the senior category by solving a Rubik's Cube in 5 minutes and 49 seconds. But he didn't stop there. He also set two other records for the 2 by two cube in his age group, both for best single time and best average time. His girlfriend was even there to cheer him on. What'd you tell him? >> I told him, I said, "Pretend you're home watching TV like you always and he doesn't train two and a half." >> I know. >> Cuz I know he can do it. >> It's different doing it by yourself and under pressure like that against the clock, you know. I get a little flustered, you know. >> Oh, you did great. >> I was relieved. >> The members of the Buffalo Speed Cube Club were also there to celebrate his wins. But even with his newfound fame, the club members say they still plan to meet every Tuesday night at the library to get their cube on. Today's story getting a 10 out of 10 shows us that you're never too young to be a hero. When a fire broke out in his apartment building, 9-year-old Savage knew exactly what to do. All because he says he paid attention in school. >> My mom was baking pizza and she yelled that there's a fire. I told my dad to pull the fire alarm and the call 911. I made sure that everyone evacuated from the building. The Mount Lebanon Fire Department in Pennsylvania says Savage participated in school fire safety lessons and that his quick response kept the fire from becoming catastrophic. >> Being able to prevent that from happening, knowing our kids know what to do so that they can help themselves, that's fantastic. >> The partnership has been teaching fire safety in elementary schools in the area for 30 years. Savange says those lessons can make a real difference. >> You can be a hero if you listen class. You can buy stuff at any time, but you can't. Life is priceless. >> All right, superstars. Congratulations to today's Your Word Wednesday winner. That's Miss Peterson at Nose Creek School in Calgary, Canada, who submitted obiate, a verb meaning to anticipate and prevent something such as a situation or make an action unnecessary. Thank you for making us all a little bit smarter today. I also have one shout out for you today. Miss Janice at Rston High School in Rston, Nebraska. Thank you for subscribing to our YouTube channel. And thank you so much to all of you for spending part of your day with us. Koi will be right back here tomorrow. I'm Mina Derson and this is CNN 10.