I once wrote a web service that I deployed and then never had to maintain. I still have not discovered any bugs in it, and it has not needed any new features. It's still running now and has thousands of users a day.

That code is beautiful because I never have to look at it or tinker with it.

(For those wondering about security, it is deployed in containers that are destroyed and rebuilt from patched images on a daily basis. It does not use any web-hosted libraries.)