My interest in the history of math is one of the factors that propelled me into teaching. I wrote my master's thesis on incorporating the culture and history of math into its teaching. I often incorporated math history in my teaching and developed several side presentation that provided historical background and insight. Students commented that this was their favorite part of my class.
The links below point to these presentations. The presentations are not self contained — there are no slide notes and so my more detailed verbal explanations them are not available. They are at an intermediate high school level except for The Basel Problem, which requires some pre-calculus.
Some of the earlier presentations have little or no attribution for the photos but I believe them to be all in the public domain or properly used under US Fair Use copyright laws.