Azulejo is a form of Portuguese and Spanish painted tin-glazed ceramic tilework. Azulejos are found on the interior and exterior of churches, palaces, ordinary houses, schools, and nowadays, restaurants, bars and even railways or subway stations. They are an ornamental art form, but also had a specific functional capacity like temperature control in homes.

There is also a tradition of their production in former Portuguese and Spanish colonies in North America, South America, the Philippines, Goa (India), Lusophone Africa, East Timor, and Macau (China). Azulejos constitute a major aspect of Portuguese architecture and Spanish architecture to this day and are fixtures of buildings across Portugal, Spain and their former territories. Many azulejos chronicle major historical and cultural aspects of both Portuguese and Spanish history.

Source: Wikipedia