My two-hour demos normally include me painting 2 watercolours.  As a rule, I like to paint a scene very local to the venue.  So a shortlist of photos are presented to the attendees, and a vote is taken on which 2 to paint.  So my visit to Cowbridge Art Society had these 4 photos as the choice:

The most popular 2 were the Physic Garden top right and Ogmore Castle bottom left.  So each of the following paintings were done in under an hour, with a bit of commentary from me along the way:

Above - Ogmore Castle

Above - The Physic Garden (bit of a rush to complete this one!)

Both painted on Saunders Waterford, Cold Press, 300 gms