Artemis smiled. It was Gaudi himself. How amazing. 
The scene solidified, colours painting themselves brighter. Artemis could smell the dry Spanish air now, and the heavy tangs of sweat and paint. 
'Excuse me?' said Artemis in Spanish.
Gaudi looked up from the drawings, and his scowl was replaced with a look of utter disbelief. There was a boy stepping from thin air. Beside him a cowering demon. The brilliant architect absorbed every detail of the tableau, committing it to his memory forever.
'Si?' he said hesitantly.
Artemis pointed to the top of the building. 'You've got some mosaics planned for the roof. You might want to rethink those. Very derivative.'
Then boy and demon disappeared.

The Lost Colony, Chapter 1