A Japanese city has a graffiti . Not spray- on walls graffiti, but graffiti in sand. City are asking tourists to stop writing and drawing pictures on the city's sand dunes. Graffiti the dunes. It ruins the people get in looking at . There were more than 3,300 cases of 'sand graffiti' at the tourist in the ten years. In January, two tourists had to erase a 25-metre-long birthday .
The Tottori sand dunes are across Japan for their . They are Japan's largest and dunes. The biggest is 50 metres high. They are 16 kilometres . They are part of a coastal park on the Sea of Japan. Tottori officials will put up to ask people to respect the dunes. The officials are tourists will not follow the . They said: "We want to continue to protect of the sand dunes."