You'll want to browse the collections at New Tretyakov Gallery - Museum of Modern Art, Pushkin Museum of Fine Arts, and Armoury Chamber. Cathedral of Christ the Savior, Grand Kremlin Palace, and Palace of Facets are notable landmarks to explore if you're in the area. You can watch performances at Moscow Arts Theatre, Maly Theatre, and Theatre on Malaya Bronnaya if you're interested in local theater.