At a recent visit to Cordoba mosque cathedral, I asked the guard where the toilets were and after pointing out where they were, he said, "no salah" and then kept a watchful eye on me the whole time I was there.

However the area where the imam would stand is inscribed with Qur'an and the whole area, indeed the whole mosque/cathedral is so serene it draws you to prayer. The urge to prostate on the floor and glorify our lord is great.  The fear of getting into trouble on a foreign country counteracts this urge . 

I prayed and prostated on the grounds outside.  But why couldn't I pray within the mosque?