The pantheon feels most special when you get to experience with few people around... There's no lines, but there are people here all the time so it's another one of the places that you might consider checking out early in the day...
Consider walking around the south side of the walls around the Vatican, seeing the relationship of the piazza to that area... There's not much north of the Vatican except a touristy shopping district...
Takes at least half a day if not longer. But ABSOLUTELY worth it. Make sure you do a guided tour. Well worth the price. We did Maximus Tours (good price, great guide): Takes at least half a day if not longer. But ABSOLUTELY worth it. Make sure you do a guided tour. Well worth the price. We did Maximus Tours (good price, great guide): http://www.vaticantou...miprivate/7…see moresee less
My daughter and I serendipitously found ourselves at the top of the Spanish Steps the night Spain won the World Cup. There must have been 10,000 people there!
Great place to chill out during the day, lovely to walk around especially when the weather is fine (summer or winter) but don't recommend going through it after dark.
If you're there for Christmas the El Corte Ingles in the centre of Madrid historically has put up a big display to celebrate the festivities - a bit like the windows in Selfridges tradition in London. Generally this is the department store in Spain historically.