Seville in Spain and it turned out to be an extremely pleasant place to spend a long weekend.
One evening we decided to go on a cruise on the Guadalquivir river - a tourist jolly, starting at the Torre del Oro (above) which is an old Moorish tower and now houses a small Maritime Museum.
Except... was it really a river? Have a looking at this Google Earth photo:
The "river" has actually been filled in higher up, so it isn't a river at all, more a elongated inlet, which explained why we couldn't see any flow. The boat turned round before getting to this point, as if to keep this a secret.
This probably relates to Seville being a working port but the river has a problem of silting, hence the long straight bit of the new channel. Large cruise ship can still make it all the way up the river to Seville as in this photo:
We did see a few rowers, kayakers and paddle boarders, but not really enough to do a Boats! Boats! Boats ... in Seville.
Anyhow, it wasn't really a real river.