National Geographic illustration of New York City Underground cross section. Amazed that we've built miles of this. :: cross-sections, very cool. it is mind boggling when you see it pictured like this.
Blueprints for the Eiffel Tower: named after the engineer Gustave Eiffel, whose company designed and built the tower. Erected in 1889 as the entrance arch to the 1889 World's Fair, it has become both a global cultural icon of France and one of the most re