L’île de la Cité is located in the 4th arrondissement in Paris and remained the center of royal and ecclesiastical power even after the city spread to both banks of the Seine during the Middle Age. Today, it is home to two institutions devoted to maintaining public order: the judiciary (Palais de Justice) and the police (Préfecture de Police)
You can admire the Notre Dame de Paris Cathedrale in the south of the island which is a marvel of the Gothic architecture and the most visited monument after the Eiffel Tower. It took 2 centuries to build it and nowadays can receive around 50 000 visitors per day!
In the North you can go to visit the Hotel Dieu and the Sainte Chapelle, and the Place Dauphine surrounded by restaurants of layers and judges.