If you could only have access to one...

...website for the rest of your teaching career, what would it be?

I posed this question at a National Maths Teacher Conference, #mathsconf5, (how long ago??!) and asked delegates who came to my workshop to leave their "Desert Island Website" on a slip of paper before they left.

I don't really know what I was expecting: a consensus maybe? A crowd-sourced ULTIMATE LIST? 

I was actually surprised by the variety of submissions (although one website did emerge as a winner!), and I present the results below :)