Sherlock Holmes remembers everything by imagining that he’s storing bits of information in a “memory palace,” a technique that originated in ancient Greece. Now, researchers have found that this method really does work to create long-lasting memories.

Users of the mnemonic technique, called the “method of loci,” mentally navigate around a familiar place, such as a path (or Holmes’ palace). To remember a piece of information, you “drop” it along the path and later retrace your steps and “pick it up.” For example, if you’re very familiar with Central Park in New York City, you can imagine walking through it, dropping the word “book” at the Boat House, then the word “water bottle” at the next bend, then the word “space” at the fountain. When you want to remember the words, you imagine retracing your exact steps.