Grant Sanderson aka 3blue1brown has a wonderful channel on Youtube where he creates accessible yet deep educational maths videos. The are literally all very good, but the last two are a really great introduction to a topic in fractal geometry, and a demystification of the Mandelbrot set, presented with supreme clarity and fantastic visualisations. Probably requires high-school or first-year undergrad maths to really understand the technical content, but if you have interest in the topic I think you would get a lot out of this even if you have no formal education.