Complex sentence: The second Sunday of October there is a popular party in Valencina de la Concepción, called "Romería de Torrijos", which has been declared festival of national tourist interest since 1998.
Split into simpler sentences: The second Sunday of October there is a popular party in Valencina de la Concepción. The "Romería de Torrijos" has been declared festival of national tourist interest since 1998.