Visitors walk along a glass path that was built of the side of a cliff 300 meters above sea level on a mountain in Pingjiang, central China's Hunan province on May 27, 2015. The 180-meter-long interactive playful musical road featuring electronic components can make visitors play a melody when walking on it. The playful path is the first one of this kind in China.[Photo/China News Service]

Visitors walk along a glass path that was built of the side of a cliff 300 meters above sea level on a mountain in Pingjiang, central China's Hunan province on May 27, 2015. The 180-meter-long interactive playful musical road featuring electronic components can make visitors play a melody when walking on it. The playful path is the first one of this kind in China.[Photo/China News Service]

Visitors walk along a glass path that was built of the side of a cliff 300 meters above sea level on a mountain in Pingjiang, central China's Hunan province on May 27, 2015. The 180-meter-long interactive playful musical road featuring electronic components can make visitors play a melody when walking on it. The playful path is the first one of this kind in China.[Photo/China News Service]

Visitors walk along a glass path that was built of the side of a cliff 300 meters above sea level on a mountain in Pingjiang, central China's Hunan province on May 27, 2015. The 180-meter-long interactive playful musical road featuring electronic components can make visitors play a melody when walking on it. The playful path is the first one of this kind in China.[Photo/China News Service]

Visitors walk along a glass path that was built of the side of a cliff 300 meters above sea level on a mountain in Pingjiang, central China's Hunan province on May 27, 2015. The 180-meter-long interactive playful musical road featuring electronic components can make visitors play a melody when walking on it. The playful path is the first one of this kind in China.[Photo/China News Service]

Editor: Lucia Su