Today, we"re floating across the waves, following the ocean currents to Japan. Marine Day—海の日, Umi no Hi in Japanese—is celebrated on the third Monday of July. Japan is made up of 14,125 islands and has 29,751 kilometres of coastline, so it"s no wonder the sea plays such a key role in national life. As well as providing much of the country"s food, the seas that surround Japan are vital for trading and communicating with other nations.