Designed by French engineer Ferdinand Arnodin and opened in September 1906 by Viscount Tredegar, Newport Transporter Bridge spans the River Usk, and is one of only seven such structures in the world. With towers 645ft apart, and a height of 242ft it can be seen from miles around. This unusual design was chosen because the Usk has a wide tidal range, and it was important to to keep the river open for the tall masted ships of the time. It was also a less expensive option than a tunnel. Several more conventional bridges have since been built at Newport, and the Transporter Bridge is now only open at weekends.