Today we decided to take a train to the city of Oxford, about 1-1.5 hours out of London. The Universities in the city are amazing. The grounds are immaculate and the buildings are incredible. We visited Christ Church University, the location sight for filming of the Harry Potter. Being Harry potter fans, this was extremely fun for us. We stood in the Naive of the University and it felt like we were standing in Hogwarts. Such a surreal experience.
If you are in London and have the time, I would definitely recommend a day trip here. We jumped on a Red tour bus which took us to everywhere we needed to go plus gave us insightful information.
From London we caught the "fast train" from Paddington Station.
Hint: Travelling 'off peak' during the day saves you money
What to do
When you arrive via train, there is a tourist information booth in the station. Here they can give you tips and you can purchase tours, hop-on-hop-off bus tickets etc.
It is close enough to get to the main sights by foot however given we were only there for one day, my brother and I opted for the hop-on-hop-off bus, which I recommend doing because not only do you get a history lesson, you also get dropped off at the big universities and main sights.