Get a sense of scale for computer storage...

Byte of data: a grain of rice
Kilobyte: a cup of rice
Megabyte: 8 bags of rice
Gigabyte: 3 container lorries
Terabyte: 2 container ships
Petabyte: covers Manhattan
Exabyte: covers the UK (3 times)
Zettabyte: fills the Pacific Ocean

Original source of the comparison, for the record: https://www.slideshare.net/dwellman/what-is-big-data-24401517