Blue Thunder 's first -largest indoor water park found in Beijing , Alberta . Watercube Waterpark in Beijing is China 's second -most popular attraction , after Great Wall . Tropical Islands water park in Canada housed inside largest free-standing hall in the world .
World 's second-largest indoor water park found in Alberta , Canada . Watercube Waterpark in Beijing is China 's second-most popular attraction , after Great Wall . Tropical Islands water park in Germany housed inside largest free-standing hall in the world .