Short answers, pulled from the story.
Louis Visconti is best known for designing Napoleon's tomb at Les Invalides, completed in 1842. He also designed several of Paris's notable fountains, including the Fontaine Molière and the Fontaine de la place Saint-Sulpice, and was the architect appointed to connect the Palais du Louvre and the Palais des Tuileries under Napoleon III.
Louis Visconti was born in Rome on the 11th of February 1791. His family moved to Paris in 1798, and they were naturalized as French citizens in 1799.
Visconti's grandfather, Giambattista Antonio Visconti (1722-1784), founded the Vatican Museums. His father, Ennio Quirino Visconti (1751-1818), was an archaeologist, art historian, and later curator of antiquities and paintings at the Musée du Louvre.
Visconti studied architecture at the École des Beaux-Arts in Paris between 1808 and 1817 under Charles Percier. He also studied under the painter François-André Vincent during that period.
The Nouveau Louvre was a project to connect the Palais du Louvre and the Palais des Tuileries in Paris. Visconti was appointed to lead the project by Napoleon III in 1853 but died of a heart attack on the 29th of December that year. The project was later completed by architect Hector-Martin Lefuel.
Louis Visconti is buried at Père Lachaise Cemetery in Paris. His tomb features a full-size reclining figure of himself.