Built between 1609 and 1616, it is still used as a mosque today.
Some pics taken inside:
More than 20,000 handmade ceramic tiles line the mosque, with the colour blue dominating, hence the popular name for the mosque, actually called Sultan Ahmed Mosque.
It's worth hearing the words of Pope Benedict XVI on his visit to the mosque in 2006:
“May all believers identify themselves with the one God and bear witness to true brotherhood.” The Pope also expressed hope that Turkey “will be a bridge of friendship and collaboration between East and West”.