The Eurostar crosses the English Channel to connect the British Isles to mainland Europe. The Chunnel also carries vehicular traffic on trains. The travel agent that I booked my flights to London with suggested that I take the cheaper British Airways flights to Paris, but I insisted on taking the train. The only thing more thrilling about crossing the English Channel underwater is to crossing the English Channel by hovercraft.
Immigration and customs at St. Pancras (somehow I always think of Pancreas) Station was seamless and quick so I got to the right platform in a matter of minutes. Be sure to spend some time at the VAT redemption counter to get some of that hefty 20% VAT returned to you before you leave! The train was really crowded that day, not sure if it’s a normal thing or if it was just because that day was the 70th anniversary of WWII.
Train or plane? Hovercraft, definitely.