A white building across the square looked strangely familiar.

Could it be like St.Paul's which Philip had been taken to see when he was very little, and which he had never been able to remember?
No, he could not remember it even now.

The two prisoners looked out in a long silence.

Far below lay the city, its trees softly waving in the breeze, flowers shining in a bright many-coloured patchwork, the canals that intersected the big squares gleamed in the sunlight, and crossing and recrossing the squares and streets were the people of the town, coming and going about their business.
'Look here!' said Lucy suddenly, 'do you mean to say you don't know ?' 'Know what ?' he asked impatiently.
'Where we are.

What it is.