A "tsunami bomb" was tested off the coast of New Zealand

Not recently, of course. But during World War II, such a device was tested around New Caledonia and Auckland as a back-up option for use against Japan should the Trinity test fail. The New Zealand tests showed that "the weapon was feasible and a series of 10 large offshore blasts could potentially create a 33-foot tsunami capable of inundating a small city."

The top secret operation, code-named "Project Seal", tested the doomsday device as a possible rival to the nuclear bomb. About 3,700 bombs were exploded during the tests, first in New Caledonia and later at Whangaparaoa Peninsula, near Auckland.

The plans came to light during research by a New Zealand author and film-maker, Ray Waru, who examined military files buried in the national archives.

"Presumably if the atomic bomb had not worked as well as it did, we might have been tsunami-ing people," said Mr Waru.

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