If you plan to travel between the UK and mainland Europe, I highly recommend the ferry across the Channel. Although the Channel Tunnel Train can be exciting, you miss out on the stunning views above. If you’re looking for speed, then by all means.
I caught an overnight ferry from Calais to Dover, and let me tell you, watching the sunrise at 4am over the White Cliffs of Dover was a surreal experience – not something to be missed.
Ferries can easily be booked online via the P&O Ferries site. Crossings are made multiple times a day, and take a short 1h30m.