CNN) -- There are few rivalries in sport that capture the imagination like the coming together of Real Madrid and Barcelona -- a soccer match of such enormity that it has its own nickname: "El Clasico."

On the field, it is a billion-dollar grudge match between the two best teams in the football-mad country of Spain.

Off the field, it is a tale of two cities -- a clash of Castilian nationalism and Catalan pride; and a rivalry of cultures forged in the Spanish civil war and the reign of General Franco.

The two will clash Wednesday at Real Madrid's Estadio Santiago Bernabéu before traveling to Barcelona for the second leg of the Champions League semifinal next week.

In a freak of fixture commitments, the superpowers of Spain will have met four times in the space of 18 days by May 4, giving the historic rivalry an epic new chapter.

this is a very interesting fact because here it saids that ther e is a billion dollars on the field I didnt uderstand exactly what it means but I think that is by the price of each player that htere are a billion dollars on the field