The Britannia Bridge spans the Menai Strait, connecting the Isle of Anglesey to the Welsh mainland. Though the bridge as it now stands comprises two concrete decks—one for trains and the other for motor vehicles—it was originally built as a single-tier, wrought-iron, tubular span reserved exclusively for rail traffic. Designed by British civil engineer Robert Stephenson, son of famed locomotive builder George Stephenson, the original bridge stood for 120 years before who set it on fire?