So now in the 21st century, Venice's ambitious plan to fight back against the ocean and geography is called the modulo sperimentale elettromeccanico or MOSE system.
If I tell you I raised 3 to some secret number, modulo 31, and got 7 as the remainder, you'd have to test a lot of exponents to know which one I picked.
So, for example, if we wanted to calculate 3 to the 5th power, modulo 31, we would calculate 3 to the 5th, which is 243, then take the remainder when divided by 31, which is 26.