Browser game.

With this great explainer video by Alt Shift X.

Landsat images comparing greater Cairo (particularly the eastern half) from 1984 and 2019.
Lots of good references.

Discusses entropy as a measure of password strength, and includes two useful tables.
For example, a 30-character password using alphanumeric characters (mixing both small- and upper-case letters) achieves around 160 bits of entropy.

The article also includes guidelines for strong passwords, reproduced below:

• Use a minimum password length of 10 or more characters if permitted.
• Include lowercase and uppercase alphabetic characters, numbers and symbols if permitted.
• Generate passwords randomly where feasible.
• Avoid using the same password twice (e.g., across multiple user accounts and/or software systems).
• Avoid character repetition, keyboard patterns, dictionary words, letter or number sequences.
• Avoid using information that is or might become publicly associated with the user or the account, such as username, ancestors' names or dates.
• Avoid using information that the user's colleagues and/or acquaintances might know to be associated with the user, such as relative or pet names, romantic links (current or past) and biographical information (e.g., ID numbers, ancestors' names or dates)..
• Do not use passwords which consist wholly of any simple combination of the aforementioned weak components.