This richly detailed structure is the Arc de Triomf, which along with the plaza, were the gate and grand entrance for the exposition held in Barcelona in 1888. It’s built in the Moorish Revival style and was completed one year before the Eiffel Tower in Paris, featured in the 1889 World’s Fair.
Expositions were popular throughout Europe in the 19th Century, and were a way for countries to advertise their cultures and industries.
No expense was spared for constructing the Barcelona Exposition, and the workmanship and artistry were excellent. Unfortunately, many of the buildings were destroyed long ago. After looking at this plaza and arc, you can see what a loss this is.
Do you have an exposition building in your country that you enjoy?