Today is National Pizza Day so here’s 5 things you may not have known about pizza

Better than December 25 or even your own birthday, February 9 is arguably the greatest date on the calendar, purely because it is National Pizza Day.

With over three billion pizzas sold in the U.S. alone every year - which doesn't even include home-cooked frozen pizzas! - there is nothing brings us all together faster, or makes us fight harder, than pizza. Have you ever tried to settle on toppings if there's more than two people in the room? You may as well be trying to organise a G8 summit. In celebration of National Pizza Day, here's some facts about one of the world's favourite comfort foods that you may not have known. The world's largest pizza was over 131-feet in diameter Back in 2012, five Italian chefs collaborated on making the record breaker, with the monster pie containing 19,800 pounds of flour, 10,000 pounds of tomato sauce, 8,800 pounds of mozzarella cheese, 1,488 pounds of margarine, 551 pounds of rock salt, 220 pounds of lettuce and 55 pounds of vinegar. It weighed 51,257 pounds, but thankfully it was also gluten-free, so it kinda balances out. The first recorded use of the word "pizza" was in 997 AD However, pizza historians (that's a thing, right?) theorise that it wasn't until late 18th century when the food-geniuses in Naples added tomatoes into the mix, as prior to that the pizza toppings were almost exclusively cheese, garlic and... lard. Gross. The most expensive pizza in the world costs just shy of €10,000 No, that isn't a typo. Topped with three types of caviar, Norwegian lobster and hand picked grains of pink Australian sea-salt (?!), this pizza can only be made in your home, and only if you happen to live south-western Italian town of Salerno, and you give them three days warning to properly prepare the dough. Oh, and if you happen to have more money than the Sultan Of Brunei. Those who eat more pizza have been shown to be less susceptible to certain types of cancer While there is still some debate over whether or not those who simply stick to a generally healthier Mediterranean diet, or if it's the heightened presence of lycopene (the type of tomatoes used in certain pizzas), studies have shown that Italians who eat more pizza have lower incidences of cardiovascular diseases and digestive tract cancers than those who eat less pizza. Like we needed another reason to eat more pizza! Toppings around the world go beyond just pepperoni and cheese While the options available to go on your pizza from your local take-away can already be overwhelming, the choices when you go abroad are... how do we put this?... eclectic. Local pizza favorites include horse-meat (Denmark), coconut (Costa Rica), mushy peas and raisins (Brazil), peanuts and bananas and curry powder (Sweden), and smoked reindeer (Finland, poor Rudolph!). But even with all of those options, there is still the eternal debate to be answered: