Learning how to calculate the circumference of the Earth using the technology the Ancient Greeks had = a fun, practical way to approach maths, which also incorporates history. Also, trying to solve 'ancient problems' using limited resources is a great way to develop divergent thinking, and to help students understand that we too, need to 'think outside the box' in order to make progress; it's not a given like on a Civ tech tree.

Learning how various religions suppressed scientific development and set us back 1000 years is a good warning sign for future generations not to put faith into 'one truth'. Showing the importance of questioning everything and being curious is a precursor for scientific development.