We spent the day in Cardiff, with the highlight of our day being to visit the grand and magnificent Cardiff Castle. The architecture is beautiful, the decoration is detailed and there's a brilliant lookout point where you can see almost all of Cardiff surrounding the castle grounds.
How to Get to Cardiff
We took a morning train into Cardiff across the English-Welsh border. Trains run directly from London and take about 2 hours. You can buy train tickets at any UK railway station, or you can purchase them online from Trainline in advance (they're often more expensive last minute).
How to Visit Cardiff Castle
Although you can do a self-guided tour and visit at your own pace, I highly recommend the guided tour of Cardiff Castle. The tour guides are very knowledgeable, and will lead you in around the castle so you don't miss any of the crucial parts that are the most fascinating. They also point out some of the fascinating secrets that may be easily missed by the untrained eye, like certain panels and ceiling art. Tickets are £12.50 per adult for entrance to the castle, with an additional £3.25 charged for the tour (so worth it!).