KOBE ¨C Kobe¡¯s Minatogawa Zuido, Japan¡¯s oldest water tunnel, has been turned into a concert hall 15 years after it ceased carrying a river.

The tunnel was built in 1901 to change the course of the Minato River in the wake of a flood in 1896. With a height of 7.7 meters and width of 7.3 meters, it was one of the largest river tunnels in the world at that time.

The tunnel is lined with 4.5 million bricks. The way they lie, supporting sidewalls and arches, testifies to the advanced architectural skills available at that time.

Minatogawa Zuido was damaged in the 1995 Great Hanshin Earthquake and was deemed unfit for further use as a watercourse. It was replaced by a new tunnel in 2000 but has been preserved as a valuable piece of modern civil engineering heritage.

¡°We hope visitors recognize the enthusiasm of builders more than 100 years ago from the large scale of the tunnel and from its walls, adopting the most advanced construction methods of that time,¡± said Junichi Ichinari, 67, secretary-general of a civil group formed to preserve the structure.

The tunnel was opened to the public on a regular basis in 2006 and from time to time it was used as a venue for concerts. Acclaim grew, and from 2009 concerts were held regularly.

At present, the tunnel is open to the public on the third Saturday of every month. Concerts start at 1:30 p.m. and last one hour.

Artists who have performed there include the brass band of a local junior high school. Recently, a pair of players of crystal singing bowls took advantage of the acoustics, performing under orange lights set up 100 meters from the entrance before an audience of around 140.

Yuko Nakano, 56, one of the players, said the echoing sound of the crystal singing bowls in the tunnel has a more ¡°relaxing effect¡± than in other places.

¡°Regular visitors are increasing thanks to concerts,¡± Ichinari said. ¡°We expect them to find new aspects of the tunnel through repeated visits.¡±