Today is March 14, a day celebrated as Pi Day all over the world. First instituted in 2009 by law in the US House of Representatives, the day has now become a global phenomenon. Researchers, scientists and math lovers worldwide come together to celebrate a day wherein math and real life coincide.

Pi is a mathematical constant that is often used to calculate the circumference of a circle. Its value is 22/7, or 3.141…, due to its being an irrational number. It is widely considered as the most unique and pervasive mathematical number due to its infinitely calculable nature.

Incidentally, today is the 10th official Pi Day as per the ruling in the US. However, the day has been celebrated for a long time, and even coincides with the birthday of prominent physicist Albert Einstein. One of the special Pi days that took place recently was that of 2015. At exactly 9:26:53 on March 14th of that year, the clock showed 3.141592653, which are the first 10 digits of pi.

The number is of great importance to mathematicians, who have even gone so far as to call it “transcendental”. However, the convenience of using Pi has been questioned, as the mathematical constant Tau, which is simply Pi multiplied by 2, is easier to use in formulae. However, the infinitely random nature of Pi has made it a draw for mathematicians, as they seek to find patterns in the numbers.

On this day, scientists celebrate by having Pi-themed competitions, some of which include Albert Einstein look-alike competitions. Another long-standing tradition is also to eat pie, due to it sounding similar to the number.

There has also been a long-standing competition to compute the most digits of Pi that is humanly possible, at least before the 21st Century. The 100th digit calculation of Pi took place only in 1706 when Abraham Sharp decoded the first 100. The 200-mark was broken in 1824 by William Rutherford, with the number going up to 707 in 1874.

The rise of supercomputers sped up the discovery of more digits, with the ENIAC in 1949 taking 70 hours to calculate 2,037 digits. In 1973, the CDC 7600 supercomputer took just under 24 hours to calculate 1,001,250 of Pi. The 1 billion-mark was broken by the T2K Open Supercomputer, which took 29 hours to calculate 2.5 billion digits.

However, the record is held today by Peter Trueb, who took over 100 days to calculate 22.4 trillion digits of Pi in 2016. This effort took over 120 TB of hard disk space and 4 server-grade processors to achieve and remains one of the biggest advances when it comes to calculating the number.