Among them in Spain, the Alcazar, Alhambra, Gaudi's unfinished marvel of a cathedral in Barcelona, Cordoba and its mosque, Lisbon cathedral and it's beautiful lacy cloisters, Roman aqueduct in Segovia, the glorious international pavilions of Seville [especially their own Spanish pavilion where a scene in Star Wars 2 was filmed], and Valencia's railway station [utterly gorgeous inside].
Wales is a green historical gem. Highlights there? Anne Hathaway's chocolate box thatched cottage, stumbling upon a bluebell wood on a country lane, the dripping gold of Bodnant gardens' viburnum arch just emerging into bloom, Caernarvon castle, walking across a canal aqueduct in the rain, Llanthony priory ruin, colourful Portmerion, Powis castle, Skirrid Inn [oldest in Wales] and Valle Crucis abbey ruin.
In Kent and Sussex, besides the luscious early spring gardens, Bateman's [Kipling's home], Brighton pavilion, Canterbury cathedral, Dover and Hever castles were all visual and sensual highlights.