Rephotography and colourising
Take two photos up to 170 years apart in the same spot, stick them together in a popular piece of imaging editing software. Alternatively, find an old photo and colour it in in, it's quite relaxing just like it used to be when you were little, tongue sticking out of the corner of your mouth in a half trance colouring in lineart pictures on cheap paper, et Voila. Parlour tricks my friends. And if it gives people a window into something they wouldn't otherwise see, then all well and good.