Butler County Heritage Center, 119 W. New Castle St., will display two model railroads on Sunday afternoon. Hours will be noon until 4 p.m. In addition to a small, new train display, the Heritage Center is also home to the Jay Bee Miniature Circus, Austin and Bantam cars as well as the "jeep," which was produced in the city of Butler, and exhibits about Pullman-Standard, steel, oil and glass industries. Museum admission is $5 for adults, $2 for children 5 to 17, and free for those under 5. Call 724-283-8116.

Harmony Museum on Mercer Street in Harmony, representing the town founded in 1804 by pacifist German Lutheran Separatists and their Harmony Society, displays the annual Yobp-Eckstein log house village and toy railroad display in the Wagner House museum annex through early January. Guided tours are offered from 1 to 4 p.m. daily except Mondays and holidays; reservations are suggested for weekends and required for groups. Call 724-452-7341 or 888-821-4822, or see www.harmonymuseum.org.

<B>Pittsburgh Children's Museum</B>, 10 Children's Way, Allegheny Square, continues "Tough Art" through Jan. 18, presenting the work of four artists who made art "tough" enough to withstand kid handling. Family Yoga is held from 12:15 to 12:45 p.m. Fridays in January. Regular hours are 10 a.m. to 5 p.m. Mondays to Saturdays; and noon to 5 p.m. Sundays. Admission is $9 for children 2 to 18 and senior citizens and $10 for adults; children younger than 2 are admitted free. Parking is $3 for members, or $5 for nonmembers in the museum's lots. On-street, metered parking is also available. Call 412-322-5058 or see www.pittsburghkids.org.<B>Carnegie Museum of Natural History</B>, 4400 Forbes Ave. in Oakland, is displaying five Christmas trees decorated along the theme "Pittsburgh 250" through Jan. 8. Neapolitan Presepio continues through Jan. 7. Continuing is "Born of Fire: The Life and Pottery of Margaret Tafoya" through Jan. 4 and "Dinosaurs in Their Time." Hours are 10 a.m. to 5 p.m. Tuesdays through Saturdays, with additional hours until 8 p.m. Thursdays, and noon to 5 p.m. Sundays. Closed major holidays. Admission, which includes the Carnegie Museum of Art, is $15 for adults, $12 for senior citizens, and $11 for students and children age 3 and older, and free for members and children younger than 3. Call 412-622-3131 or see www.carnegiemnh.org.<B>Phipps Conservatory and Botanical Gardens</B> in Schenley Park is displaying among the plants some Donald M. Robinson photographs of the Chihuly glass that was exhibited at Phipps last year. The photography will be shown through Jan. 22. Phipps is open daily from 9:30 a.m. to 5 p.m. and until 10 p.m. on Fridays. Admission rates are $10 for adults, $9 for seniors age 62 and older and students with ID, and $7 for children 2 to 18. Phipps members and children under 2 are admitted free. Call 412-622-6914 or see www.phipps.conservatory.org.<B>Carnegie Science Center</B>, One Allegheny Ave. next to Heinz Field on the North Side, is offering ongoing displays such as the Miniature Railroad & Village. The traveling exhibition "Hubble Space Telescope: New Views of the Universe," continues through Jan. 12. Regular hours are 10 a.m. to 7 p.m. Fridays and Saturdays and from 10 a.m. to 5 p.m. Sundays through Thursdays; closed holidays. Regular admission is $14 for adults and $10 for senior citizens age 62 and older and children 3 to 18. Parking is $3. Call 412-237-3400 or see www.carnegiesciencecenter.org.<B>Heinz History Center</B>, 1212 Smallman St., features its new exhibit, "Pittsburgh: A Tradition of Innovation," tracing Western Pennsylvania's imprint on the United States and the world. From the Meadowcroft Rockshelter in Avella, 16,000 years ago to the roads, planes and houses of today, the long-term exhibition features people's stories. Hours are 10 a.m. to 5 p.m. daily, except holidays. Admission is $9 for adults, $7 for senior citizens older than 61, $5 for students with ID and for children ages 6 to 18, and free for children younger than 6. Call 412-454-6000.