March 14^{th} saw the worldwide celebration of International Day of Mathematics (IDM). The theme this year was ‘Mathematics Unites’. Why is it celebrated on this day? Because this day is also referred to as 3/14. Does this number sound familiar? You are right, the mathematical constant *π* or Pi is approximately 3.14! *π* is the ratio of the circumference of a circle to its diameter. ^{[}1^{] }^{}The 2022 IDM is part of the activities of the International Year of Basic Sciences for Sustainable Development 2022 (IYBSSD 2022).

Speaking of numbers, do you know how deep the ocean is? The average ocean depth is approximately 3.7 kilometers! The deepest point in the ocean known so far is Challenger Deep, in the Mariana Trench, at approximately 11 kilometres! The Mariana Trench is located in the western Pacific Ocean. ^{[}2^{]} Explore the Map of the Week to learn more about mean underwater depth in the European region. Click on any location in the map to see what the local mean underwater depth is.

Given these impressive depths, it is not surprising that Principle 7 of Ocean Literacy states that ‘The ocean is largely unexplored’. The ocean is the largest unexplored place on Earth. New technologies, sensors and tools are expanding our ability to explore the ocean system. This includes satellites, drifters, buoys, subsea observatories and unmanned submersibles. Mathematical models also help us understand the complexity of the ocean and of its interaction with Earth’s interior, atmosphere, climate and land masses. ^{[}3^{] }A great reason to study and celebrate mathematics! But it is not limited to mathematics. Interdisciplinarity is key to ocean exploration. It requires close collaboration among biologists, chemists, climatologists, computer programmers, engineers, geologists, meteorologists, physicists, animators and illustrators. ^{[}3^{]} If you are interested in ocean exploration, you are surely also interested in Science, Technology, Engineering, and Mathematics (STEM)!

The data in this map are provided by EMODnet.

^{[}1^{] }http://www.nasa.gov/feature/jpl/pi-day-challenge-solve-math-problems-with-nasa^{}

^{[}2^{] }http://www.nhm.ac.uk/discover/quick-questions/how-deep-is-the-ocean.html^{}