Distribution of maximum values
What does the distribution of maximum values look like? A sample is taken from the parent distribution and the largest value is extracted. This is repeated many times to build a distribution of maximums.
For example, the parent distribution might represent a daily value, and the extremal distribution would be composed of the largest value each year from 365 daily values.
The bigger the sample size, the higher the values in the distribution of extremes. Despite various parent distributions, the extremal distribution tends towards the same shape.