Here is an introductory video by World Site Guides, with the calming background music that seems to be deemed essential for such productions:
Detailed information, with excellent illustrations, is given in Peter van der Krogt's remarkable website on Columbus monuments around the world.
As with all Barcelona monuments, the essential local source is the Art Públic site, which also appears with suitably calming music. Remembering the date (1888), the entries on the monument can be found in a few clicks.
as for the great question, was Columbus in fact Catalan? The case is summarised here, and discussed in exhausting detail on the Catalan Wikipedia entry.