Riverdance World Record Longest Line 21st July 2013 - What a fantastic day on the banks of the River Liffey. A sincere thank you to all who made it happen .brIrish dancers have set a world record in Dublin for the longest Riverdance line. More than 2000 people from 163 dance schools in 44 countries gathered on the .brRiverdance World Record Longest Line 21st July 2013 - What a fantastic day on the banks of the River Liffey. A sincere thank you to all who made it happen .brSee for details of the Longest Riverdance .