You would travel in a Northwestern direction, and would go over the English Channel.
You'd need to cross the English Channel to go from London to Paris. If you're going by rail, you cannot cross OVER the Channel - but you can cross UNDER it. To Vienna, you'll cross a great number of rivers, but the most important is probably the Rhine. Lots of bridges that way.
It depends where your starting point is.
London, Paris, and Vienna are surrounded by different bodies of water. London is adjacent to the River Thames and near the North Sea. Paris is located near the Seine River, while Vienna is situated along the Danube River. None of these cities are directly surrounded by a large body of water like an ocean or sea.
The Atlantic Ocean if you want to get there earlier.
If you traveled from Bangor, Maine to London, England, you would cross the Atlantic Ocean.
The North Sea
The Channel Tunnel, commonly known as the Chunnel, travels beneath the English Channel to connect London and Paris. The English Channel, located between southern England and northern France, is the body of water that the Chunnel crosses. The tunnel runs approximately 31 miles (50 kilometers) under this body of water.
English channel
the Seine river runs through Paris
London Bridge spans the River Thames.
to cross over a body of water
south america