A 404 page is a landing page that informs visitors of a website that the requested page is either unavailable or does not exist. Ideally, visitors would never land on a 404 page, however, this is not always the case, even for well-maintained sites. Having a visually appealing and user-friendly 404 error page demonstrates to customers that the website is concerned about their experience and is interested in keeping them on the website. When done correctly, a good 404 page can help users forgive the error (even if it was their own fault) and keep them on the website.