When a typhoon strikes,
one of the best places to be is Hong Kong harbour with its sheltered anchorage.

A centre of international trade,
the city is famous for its jumble of skyscrapers and its bustling commercial center.
But there's a side to Hong Kong that's less well known.
Behind the urban sprawl lies a swathe of wetlands which include the Mai Po Nature Reserve.
Managed principally for the benefit of migrating birds,
the reserve maintains a series of traditional prawn farms, known as gei wais,
and their adjoining mangroves and mudflats.
Every two weeks from November to March,
one of the gei wais is drained by opening up the sluice gates.