View of a city from above

This is a Kodachrome colour slide of a city taken from a high viewpoint, probably a tower block or other high building. I think it's London, but I can't find the round nosed building shown in the centre of the picture.

The date is just discernible on the slide as 1968, although I can't make out the month. If anyone knows the location, please let me know in the comments below.

Update: A very helpful viewer on Twitter saw this photo and pointed out that this is London. It's a view taken from the Fire Monument and looking down Monument Street towards the Billingsgate Fish Market. Thanks very much Mick Hodges on Twitter