Eurostar is a train service that connects London with Paris. It uses the tunnel under the English Channel. There is a line that connects Brussels (Belgium]) as well. Some services are operated by the GNER (Great North Eastern Railway) within the UK, from London Kings Cross to York and (from May 2002), Leeds.
London to Paris takes 3 hours. London to Brussels 2 hours and 40 minutes.
As a whole the system is attractive compared to air travel.
The company that runs Eurostar is a joint venture between Belgian, French and British railway companies. On the train itself, French, Belgian and British currency are accepted, though this should probably change with the wider introduction of the euro.
The border between France and the UK is in the middle of the tunnel. On re-entering the UK, British IND (Immigration and Nationality Department) staff are usually seen on the train.
The Eurostar leaves London from Waterloo International station.