JAPAN has become the land of the 'Super Dome' where you can ski, play baseball and even surf in a tropical paradise - without having to worry about changing climates. These gigantic enclosed leisure facilities have sprung up all over the country and the biggest development of them all, a custom-built resort on the western island of Kyushu, has just been completed. Ocean Dome at the Phoenix Resort Seagaia in Miyazaki City is the world's biggest indoor water park, covering 30,000 square metres beneath a 38-metre-high ceiling. Inside this 'tropical' beach park of palm trees, the temperature is a constant 30 degrees Centigrade and the water just two degrees cooler. The sand is really crushed marble but the world's largest artificial wave-maker enables surfers to ride 'tubes' in breakers of up to 2.5 metres. For the less energetic in this make-believe Caribbean scene there is white-water rafting, 200-metre water slides, underground caves, hot springs, rock pools and waterfalls. Caribbean dance shows are performed at night on the beach while, in 'Paradise Garden', there are restaurants, souvenir shops, a theatre and an underwater discotheque featuring the most up-to-date entertainment systems. Beyond the 'dome' is an 18-hole golf course, designed by American superstar Tom Watson, tennis courts and - just built - a convention centre. Adjoining a 43-storey 753-room hotel, it can accommodate up to 5,000 delegates. The entire resort stretches for 10 kilometres along a beach fringed by pine trees. Another recently opened facility is an indoor ski-slope, the La-La Port Ski Dome SSAWS (Spring, Summer, Autumn, Winter Skiing), in Funabashi City, Chiba prefecture. From the outside, it looks like the neck of a giant dinosaur rearing 100 metres high at its peak. Inside is a half-kilometre-long ski run, 100 metres wide, with the world's first indoor snow-making machine in the ceiling producing ultra-fine powder snow. The entire building is heavily insulated to maintain a year-round temperature of minus two degrees Centigrade. The builders claim it could even function in the Sahara Desert. It has three slopes of varying difficulty - for beginners, experienced and expert skiers. Meanwhile, the Yokohama Golf Dome in Yokohama City is elliptic - 130 metres long, 80 metres wide and 355 metres high. The dome roof keeps its shape because the air pressure inside is maintained at a slightly higher level than outside. The only completely covered golf practice range in the world, it has a 130-metre-long driving range. The Fukuoka Dome in Fukuoka City, Kyushu, was the first in Japan - and only the second in the world, following the Sky Dome in Toronto - to have a sliding roof. The stadium, home to Kyushu's only professional baseball team, the Fukuoka Daiei Hawks, contains Japan's largest baseball field and seats 48,000 people. But the most impressive statistics involve the roof which weighs 12,000 tons - equivalent to 40 jumbo jets or 10,000 cars. Even more dramatically, it hangs over the heads of spectators without the support of a single column.