Famous Photos in History in Colour

An amazing set of pictures by Reddit user mygrapefruit and self-taught picture colourer Sanna Dullaway.

I have always wondered how one would go about colouring in a black and white image and here is how one artist, I_COLORED_IT_FOR_YOU, approaches a picture.
I_COLORED_IT_FOR_YOU (_) 9 points 2 hours ago (12|3)

When doing serious colorizations, I do as much research as possible. This would involve finding color images of 1920s fashion, an updated image of the architecture and funny you should mention the color of trees as I've even researched the type of tree and used images of the bark and leaves in order to get the color just right. However, in my free time when I've been colorizing random images on Reddit, it's about 90% guesswork. I play around a lot more with the color to what I think 'looks best', so its much more of an educated guess. :)