Cadiz is an Atlantic naval and commercial port near Gibraltar. After 1492, it was a major port of entry for goods from the new world.  Dozens of watchtowers sit atop buildings near the waterfront.  Signals exchanged between the towers and incoming ships facilitated meetings for trade with local merchants.  Cadiz is the birthplace of Spanish composer, Manuel de Falla.

In south Spain, Cadiz is a port
Of both naval and merchant import
Whose rooftops embower
Many a watchtower
That aided import and export.