From Value Investing World:
The basic idea is that the human brain is better at remembering images and spatial information than it is words or numbers. If you want to remember someone’s name, for example, it is easier to remember it if you associate it with an image, and the more vivid the image, the easier it will be to remember. The memory palace is a familiar place to you (such as: a house you know well) that you can walk through in your mind, and place vivid images (such as: moonwalking with Albert Einstein) at certain points in that place (such as: at the top of the stairs) to help you remember things. As Joshua Foer described the “art” of memory:
The “art of memory” refers to a set of techniques that were invented in ancient Greece. These are the same techniques that Cicero used to memorize his speeches, and that medieval scholars used to memorize entire books. The “art” is in creating imagery in your mind that is so unusual, so colorful, so unlike anything you’ve ever seen before that it’s unlikely to be forgotten. That’s why mnemonists like to say that their skills are as much about creativity as memory.