Reminder - From Time to Time (and a hint about Challenge 22)

Here's a little reminder from The Library - but your books aren't overdue and there'll certainly be no fines! 

It's just a reminder to join in the current challenge - 'From Time to Time '  - which runs till December 15th.

I made another card for this theme:

I used some buildings - although I don't think they're in New York! - and the word 'time'. 

Please come back to The Library on December 9th for a new challenge - and you'll be walking on air when you find out what it is.