Harmony Museum, Mercer Street, Harmony, has expanded its Christmas season model railroad display. The antique Yobp-Eckstein log village and O gauge railroad is joined by an HO gauge layout. Also new is a “hands-on” wood push train for preschoolers on a tiny kids-level table. Guided tours are available from 1 to 4 p.m. daily except Mondays. Reservations are suggested for weekends and required for groups. Call 724-452-7341 or 888-821-4822, or visit www.harmonymuseum.org.

The Holocaust Center of Pittsburgh and the August Wilson Center are presenting “The Nazi Olympics: Berlin 1936” exhibit through Feb. 28 at the Wilson Center, 980 Liberty Ave. For tickets, call 412-421-1500 Ext. 106, or visit www.AugustWilsonCenter.org.Heinz History Center, 1212 Smallman St., presents “From Slavery to Freedom,” highlighting the history of the anti-slavery movement, the Underground Railroad, and the impact of 19th century activism on the modern quest for civil and human rights in Pittsburgh. “Gridiron Glory: The Best of the Pro Football Hall of Fame” continues through Jan. 6. Hours are 10 a.m. to 5 p.m. daily. Admission is $15 for adults, $13 for visitors age 62 and older, $10 for students and children ages 6 to 17, and free for children age 5 and younger. For more information, call 412-454-6000 or visit www.heinzhistorycenter.org.Carnegie Science Center, North Side, hosts Breakfast Express, which involves a journey inspired by the classic holiday film, “The Polar Express: An IMAX® Experience” on Dec. 15 and 22. Newly opened is Spaceplace, an exhibit featuring a two-story replica of the International Space Station with plenty of hands-on activities. Center admission is $17.95 for adults and $11.95 for children ages 3 to 12. Call 412-237-3400 or visit CarnegieScienceCenter.org for more information. The center will be closed all day Sunday for the Steelers game next door at Heinz Field. Regular hours are 10 a.m. to 7 p.m. Saturdays and 10 a.m. to 5 p.m. Sundays through Fridays.