Europe's first high-speed international trains to use solar panel generated electricity were introduced Monday. The trains link the cities of Paris and Amsterdam.
Solar power is used in a 3.6 kilometer (about 2 mile) stretch of tunnel crossing Antwerp, Belgium. 16,000 solar panels were installed on the tunnel's roof and cover an area of 50,000 square meters (about 12 acres.)
The project costs about $22.8 million.