The Eiffel Tower is a symbol of Paris. It was built during the 1889 Universal Exposition and at 320 meters tall, was the largest structure in the world at the time. Due to its popularity, the Tower was left standing after the Expo and has since become the defining icon of the Paris skyline.
The elevators on the north and west legs connect the three viewing platforms. You can visit the second platform by elevator or stairs, but be warned that there are no less than 1665 steps.
As an anecdote, it’s a rather common occurrence to see couples proposing on the tower. Also, every night the twin lamps on the Eiffel Tower shine out for 80 kilometers.