Some of the world's most extensive sea defences did little to protect Japan's coast from the devastating tsunami so is it time to develop buildings that can withstand the impact when it comes?The Japanese government has invested heavily In seawalls and breakwaters, which stretch along some 40 per cent of the country's 30,000km coastline. The policy reflects a general belief by authorities in tsunami prone regions around the world that concrete barriers offer the best hope of protection from the sea. Indeed. that may be true for smaller storms, but the disaster in Japan illustrates that seawalls offer precious little protection against the most ferocious tsunamis. Many coastal engineers are now calling for a shift in policy. Rather than trying to keep the sea out by building ever higher walls, more lives might be saved by designing buildings that can withstand the waves - an a research that up to now has received little funding.