Le Marché des Enfants Rouges, which opened in 1615 as a vibrant food hall, was a fixture for chefs, cooks and tourists.

© Sarah Meyssonnier/Reuters

Our reporter, John Branch, joined a team installing cameras in the Sierra Nevada for detecting wildfires. Artificial intelligence is used to sift through images from the network, helping firefighters identify and respond to early to signs of wildfires.