The bitter rivalry between Manchester United and Liverpool is now played out on a global stage but the origins of the divide are deeply rooted in the battle for supremacy in England's northwest. United and Liverpool, who both play in red, have a combined tally of 38 English league titles and eight European Cups and both enjoy a vast following throughout Britain and around the world. For all the rancour between fans of the country's two most successful clubs, located just 30 miles (48 kilometres) apart, they share much in common -- a history of enviable success but also of deep tragedy.
Last month United marked the 60th anniversary of the Munich air crash that killed 23 people, including eight players, on their way home from a European Cup quarter-final in Belgrade.
In 1989, 96 Liverpool fans were killed in a crush at Sheffield Wednesday's Hillsborough ground as they attended an FA Cup semi-final.
"They have a global profile cities of a similar size don't have and United and Liverpool have given them that profile," Andy Mitten, editor of the United We Stand fanzine, and Manchester native, told AFP.
"These are two huge clubs with similar histories of triumph and tragedy that hail from cities that punch well above their weight demographically."
The two sides first met as far back as 1894 -- in the same year as the opening of the Manchester Ship Canal, which sparked tension between the rival cities by undermining Liverpool's position as a commercial port.
However, most of their success has been condensed into two prolonged spells of domination. Rarely have both clubs been on an upward curve at the same time.
Liverpool left their rivals in the shade during a prolonged period of dominance from 1973 until 1990, winning 11 league titles and four European Cups.
Alex Ferguson, who arrived at Old Trafford in 1986, famously described "knocking Liverpool off their perch" as his biggest challenge as United manager and he duly delivered, ending the Red Devils' 25-year wait to win the league, scooping up 13 titles and two Champions League crowns.