the 2011 Tōhoku earthquake and tsunami, the seawalls in most areas were overwhelmed. In Kamaishi, waves surmounted the seawall – the world's largest, erected a few years ago in the city's harbor at a depth of , a length of and a cost of $1.5 billion – and eventually submerged the city center. The risks of dependence on seawalls was most evident in the crisis at the Fukushima Dai-ichi and Fukushima Dai-ni nuclear power plants, both located along the coast close to the earthquake zone, as the tsunami washed over walls that were supposed to protect the plants. Arguably, the additional defense provided by the seawalls presented an extra margin of time for citizens to evacuate and also stopped some of the full force of energy which would have caused the wave to climb higher in the backs of coastal valleys. In contrast, the seawalls also acted in a negative way to trap water and delay its retreat. The failure of the world's largest seawall, which cost $1.5 billion to construct, shows that building stronger seawalls to protect larger areas would have been even less cost-effective. In the case of the ongoing crisis at the nuclear power plants, higher and stronger seawalls should have been built if power plants were to be built at that site. Fundamentally, the devastation in coastal areas and a final death toll predicted to exceed 10,000 could push Japan to redesign its seawalls or consider more effective alternative methods of coastal protection for extreme events. Such hardened coastlines can also provide a false sense of security to property owners and local residents as evident in this situation. Seawalls along the Japanese coast have also been criticized for cutting settlements off from the sea, making beaches unusable, presenting an eyesore, disturbing wildlife, and being unnecessary. United States After 2012's Hurricane Sandy, New York City mayor Bill de Blasio invested $3 billion in a hurricane restoration fund, with part of the money dedicated to building new seawalls and protection from future hurricanes. A New York Harbor Storm-Surge Barrier has been proposed, but not voted on or funded by Congress or the State of New York. In Florida, tiger dams are used to protect homes near the coast. See also Breakwater (structure) Mole (architecture) General: Related types of walls: Specific walls: (Constantinople seawalls) References External links Channel Coastal Observatory – Seawalls Seawalls and defences on the Isle of