Navigo

The Carte Navigo is free (gratuite) for residents of Paris and Isle-de-France. The pass can be credited at ticket booths and machines for weekly (hebdomadaire) or monthly (mensuelle) use. If you don't have a French address you can still purchase a carte navigo découverte for 5 euros and then replenish it with weekly or monthly credits. You'll need a passport size photo to be attached to the card in order to make the purchase. Once you have it you can use it over and over again. If you're a regular traveler to Paris, consider getting one rather than buying the metro tickets. It is good on all public transportation. Above left is a photo of the Navigo-only turnstile that is in most of the métro stations entrances.

Pont Mirabeau

The French began building this bridge in 1895 during the Presidency of Sadi Carnot. It connects the 15th adn 16th arrondissements. There are three arches and the principal arch has a span of 93 meters. Interestingly, there are four allegorical statues. The one in this photo is the symbol of "Paris".