Thames River Barrier with City of London Behind

After the North Sea flood of 1953, consensus to develop protection for the City of London, which has had a flooding problem since its inception, led to the design and construction of the Thames Barrier, at a cost of £534 million (£1.6 billion in 2016).
The barrier seems to work well, and, though it is being used more than expected, plans for a larger defense structure are delayed.

London, UK

So many thanks to the late Chris Puddy for these flights. He will be missed