Chasing Liberty

Anna Foster (Mandy Moore) is the daughter of President of the United States James Foster (Mark Harmon). After Secret Service agents ruin a first date, Anna demands less supervision. For his upcoming trip to Prague, the president agrees to assign only two agents to watch over Anna, whose Secret Service codename is Liberty. In Prague, Anna and her friend Gabrielle La Clare (Beatrice Rosen) attend a concert, where Anna discovers numerous agents in the crowd. Believing her father has broken his promise, Anna eludes her protectors with Gabrielle's help. Outside the theater, she asks Ben Calder (Matthew Goode) for a ride on his motorbike. Unknown to Anna, Ben is a Secret Service agent, and he informs agents Alan Weiss (Jeremy Piven) and Cynthia Morales (Annabella Sciorra) where she can be found. When the president learns of her behavior, he instructs Ben to guard Anna without revealing his true identity, to give her the illusion of freedom with a guarantee of safety.
Believing she is finally free, Anna jumps into the Vltava River naked, mistaking it for the Danube, and she and Ben climb a rooftop to watch an Offenbach opera being shown in a plaza. The next morning, Anna calls her parents. Initially relieved that his daughter is safe, the President's tone changes when he is shown photos of her undressing. Outraged at her father's tone, Anna decides she will go to the Love Parade in Berlin. She and Ben board a train, where they meet Scotty McGruff (Martin Hancock), a flighty romantic who gives them a stack of Six Million Dollar Man stickers, instructing them to post them in random places, and one day when they are unhappy, they may come across one and it will make them smile. Ben discovers that they have boarded a Venice-bound train going in the opposite direction from Berlin.
In Venice, after checking in with agents Weiss and Moralesâwho are now growing closer romanticallyâBen joins Anna and McGruff and together they explore the city. After McGruff leaves, Anna realizes he has stolen her wallet. When Anna is recognized by tourists, she and Ben flee. With no money, they tell a kind-hearted gondolier, Eugenio (Joseph Long), that they recently married against her parents' wishes. During the free gondola ride, Ben kisses Anna to hide her from their pursuers. When he learns the "newlyweds" have no place to stay, Eugenio invites them to his house, where they are welcomed by his mother, Maria (Miriam Margolyes). That night, thinking their kiss was heartfelt, Anna offers herself to Ben, but he rejects her advances.
The next day, Eugenio drives them to the Austrian border, as Weiss and Morales show up at Maria's house and learn from Maria that Anna and Ben are married, which is then reported to Anna's parents. Upset at Ben's rejection, Anna hitchhikes a ride in a truck, leaving Ben to chase her through the Austrian countryside. Anna comes to a bridge, where she meets the Jumping Germans, a bungee jumping group. Ben arrives just as Anna is being strapped into the harness, and insists on jumping with her.
Later that evening at the Jumping Germans' camp, one of the Germans asks Anna to share his tent for the night. She refuses and flirts with Ben, who rejects her advances again. Upset, she declares that she will share the German's tent after all; Ben finally admits his feelings for Anna and they spend the night together. At the Love Parade, as Ben explains his actions on the phone to his fellow agents, Anna discovers his identity. Enraged at the apparent betrayal, Anna runs off, only to be harassed by a group of men who recognize her. Ben rescues her, and Anna and her family return to the United States.
While preparing for college, Anna reveals to her mother that her heart is "a little bit broken." At college, with Weiss and Morales (who plan to marry) still protecting her, Anna sees a Six Million Dollar Man sticker which reminds her of her European adventure. During Christmas break Anna's father tells her that Ben resigned from the Secret Service and is working as a photographer in London. During an exchange program to Oxford University Anna visits Ben at the opera, where they kiss, reconcile, and escape on his motorbike.

Question: Where did Anna Jump into naked?
Answer: the Vltava River