A coal hole is a little door that people who used to live in old houses had to use to get coal, a black rock that they used to keep stuff warm! Coal holes used to be everywhere back in the olden days when houses used coal as a major fuel source. They were usually found on the sidewalk right in front of the house. From these holes, coal was delivered to the cellar and used to keep the fireplaces going. It was a way for people to get their fuel without bringing it through the house, making everything all dirty! Nowadays, houses rarely use coal as a fuel source, so coal holes aren't really needed anymore.