These ceramic tiles, called azulejos, are one of Portugal's most iconic traditional art forms.
The designs have changed continuously over the years, evolving into the familiar ornamental tiles in blue and white.
In Lisbon they appear at almost every turn.
For almost 20 years now Leonelri Beiru has overseen the preservation of the capital's ceramic heritage.
That famous white light, the light of Lisbon, comes not only from the Tagus River and its very long estuary, but from the Portuguese sidewalks, which are white, and primarily the reflections from the tiles onto the streets.
That gives the city its special aura -- that light it's known for.
The tiles give Lisbon much of its specific character.
But aside from their decorative function, they help protect the buildings from the heat and salty air gusting in off the Atlantic, ideal for this Southern European city.
The ornamental tiles have a long history, beginning with the Moors, largely Maghreb Berbers who occupied most of the Iberian Peninsula starting in the 8th century.
The Muslim caliphates were ousted 8 centuries later, but the azulejos remained.
