While some hotels avoid having a 13th floor, others are choosing to skip the number 420, in order to deter cannabis smokers.
To most people it means nothing, but the number 420 has a long association with cannabis and is often used as a code for those in the know.
The Telegraph reported that some hotels have renamed their rooms in a bid to avoid being associated with marijuana smokers - some of whom like to steal room signs and smoke in their rooms as a celebration of the number.
An image posted on Imgur shows a room labelled "419 + 1", with a no smoking symbol in the corner.