Chaos and fractals lead to some (superficial) interest in mathematics for some time. And they are totally abstract.
You're right, the general public can be persuaded to get interested in anything that involves pretty pictures.
This is part of the reason I switched from studying semiconductor physics to giant planets. Much prettier pictures on my slides, nowadays.
It's a lot easier to get someone interested in something that they can look up at in the sky than something which is totally abstract.