Las Fallas is undoubtedly one of the most unique and crazy festivals in Spain. Then again, Spain is a country known for its unique and odd fiestas. What started as a feast day for St. Joseph, the patron saint of carpenters, has evolved into a 5-day, multifaceted celebration involving fire. Valencia, a quiet city with a population of just over 1 million, swells to an estimated three million flame-loving revelers during Las Fallas celebrations.