Ever been to Cardiff's Millennium Stadium? Well then, there's a good chance you've walked right past the hidden street concealing all those Doctor Who aliens in Face The Raven.
The scenes in which The Doctor, Clara and Rigsy discover the hidden entrance to the mysterious 'street' were filmed on Cardiff's Westgate Street, and if you look very closely at Google Maps you'll discover that there is ACTUALLY a real-life mysterious gap in the wall.
Take a closer look at the episode and compare it with Google Street View: you'll find the pub Clara walks past when she first clocks that something's up... And the same street corner she meets up with Rigsy and The Doctor on. Even Park Street turns out to be real.
So, if you've already been to Cardiff to take in Torchwood's hidden Millennium Centre entrance and Ianto's Bay shrine, you've got another reason to have a weekend away in Wales.
You might even find the mysterious Doctor Who diner while you're at it...
Doctor Who series 9 continues on Saturday nights on BBC1