Tell me about the most challenging website you created from start to finish.

While this may look like a technical question, it is actually an operational question. Rather than ask you about a specific element of web development and design, the interviewer is asking you about a process you use to develop a website. Their objective in asking this question is to determine if you have done work similar to the job for which they are hiring you. Based on your pre-interview research, you should describe a project similar to the type of work you will be doing with this organization.

"The most challenging website I have developed from start to finish is very similar to the main one your company uses. This involved online transactions and forms that users fill out to apply for the services the organization I was working for provided. The challenge was to make the website adaptive across multiple browsers and devices. I achieved this using a standard format and several different plugins available for that format."