Four of Seville's landmarks, the Real Alcázar, the Cathedral, the Giralda, and Santa Cruz, in one day, with an accredited guide and round-trip high-speed rail from Madrid included, door to door.
The AVE covers Madrid to Seville in 2.5 hours, at up to 300 km/h, no motorway, no rest stop, no half the day gone before you've seen anything. An accredited guide meets you at the station for the Real Alcázar, the Cathedral, the Giralda, and Santa Cruz, skip-the-line at both monuments, nothing to queue for.
For travelers who'd rather not give up a night in Madrid, this is Seville's landmarks in one day, door to door.