Sow and Pigs Reef
Sow and Pigs Reef is a rocky reef in Sydney Harbour, New South Wales, Australia. The reef is situated on the eastern side of the main shipping channel between Middle Head and South Head. It is  long and up to  wide. Originally the reef was exposed and resembled a sow and her litter. Explosives were used to reduce the reef, however, and now the reef is only exposed at a very low tide. A number of ships have been wrecked or damaged after hitting the reef. References

Geography of Sydney