Here is a link to an article that goes in depth explaining the hydrostatic paradox. There are images that goes along with the explanation. The pressure is proportional to the depth, the width does not affect the pressure.
http://physics.kenyon.edu/EarlyApparatus/Fluids/Hydrostatic_Paradox/Hydrostatic_Paradox.html

Below is a link to a video that explains how water towers work. It uses examples of big cities and shows where water towers would be located in them (on top of buildings). Not only does it talk about large cities, but also rural water towers.
https://www.youtube.com/watch?v=yZwfcMSDBHs

This website explains the basics of free diving such as, what is free diving, how free diving is done, and some essential materials for free diving. It also goes into depth on the various levels of free diving and how to become certified.
https://www.leisurepro.com/blog/scuba-guides/basics-of-freediving/

This website is geared toward children and explains how straws are used. It also has an example of an experiement children could use to demonstrate how straws work.
http://kidscorner.org/playlist/8-science/29-how-do-straws-work-air-pressure