This lovely walk by Dublin's Royal Canal is one of the greatest science walks, and a popular pilgrimage for geeks from around the world. We celebrate a famous Eureka moment in 1843, when Sir William Rowan Hamilton had a flash of inspiration while walking by the canal, and invented a revolutionary new type of algebra, called Quaternions. Every year, on the October 16th anniversary, hundreds of people retrace Hamilton’s footsteps from Dunsink Observatory to Broome Bridge, where he famously scratched his equation on a stone. Our tour joins the annual walk: enjoy the ballad, meet the people, explore the canal’s wildlife, science and engineering, and learn about Hamilton and his amazing algebra, which helped to land a man on the Moon!