Today is the first day of La Semana de la Arquitectura in Seville, an annual event which sees members of the public given tours of buildings around the city, by the architects who designed or restored them.
I was part of the second group to visit the Torre del Oro, the tower on the banks of the river Guadalquvir, with its architect. She explained that the building played an essential role in the defence of the city, being connected to the chain of boats across the river which was used to protect Seville from invaders.
The architect told us how the tiles on the Mudejar arches - part of the 18th-century addition - were replaced in the restoration work, which finished in 2008. Some workers, not realising their value, threw out the original tiles; replacements were sought in Morocco.
She also showed us where the original water spouts from the first addition to the tower had been - Pedro the Cruel added a section in the 14th century. The exterior of the tower was originally coated in a mixture of lime mortar and straw, which glinted in the light, and may therefore have been the source of its name (which means the Golden Tower); other theories are that it was coated in tiles; and that it was called for what was stored within its walls: gold from the New World,
After looking at the tower from its base, which is below the road level and next to the river - we could see the traces of a staircase, and where the tower formed part of the muralla (fortified city walls) - we climbed the stairs to the terrace at the top, which offers superb views in both directions along the river. The tower is 36 metres tall.
Apart from the cathedral and the bridges, what struck me most was the advancing enormity of the Torre Pelli, now dwarfing everything around it.
For details of La Semana de la Arquitectura, call 954 460 120.