Butler County Heritage Center, 119 W. New Castle St., will display two model railroads Sunday afternoons through Jan. 4. 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 ages 5 to 17, and free for those younger than 5. Call 724-283-8116.

Lowrie/Shaw House, built in 1828 by Butler's only United States senator, is open through the end of the year on Mondays, Wednesdays and Fridays (except closed Dec. 24). Hours are noon until 4 p.m., with the last tour beginning at 3 p.m. Admission fees are $3 for adults, $1 for ages 5 to 17, and free for ages 5 and under. The house museum is located at 123 W. Diamond St., directly behind the Butler County Courthouse, in downtown Butler. Call 724-283-8116 or visit the Web site, www.butlerhistory.com.

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 visit the Web site, www.harmonymuseum.org.

<B>National Aviary</B>, 700 Arch St., will offer a free child admission with the purchase of an adult admission each Sunday in December. Also, Saturday with Santa and his penguin helpers is planned from 11 a.m. to 2 p.m. Saturday. This extra program is $10 per child; adults pay regular $9 admission. Hours at the Aviary will include being open from 10 a.m. to 3 p.m. Dec. 24, closed Dec. 25, and open 10 a.m. to 3 p.m. Dec. 31 and 10 a.m. to 5 p.m. Jan. 1. Regular hours are 10 a.m. to 5 p.m. daily except Christmas Day. Regular admission is $9 for adults; $8 for senior citizens; $7.50 for children ages 2 to 12; and free for children younger than 2. Call 412-323-7235 or visit the Web site, www.aviary.org.<B>Carnegie Museum of Natural History</B>, 4400 Forbes Ave. in Oakland, is exhibiting "Born of Fire: The Life and Pottery of Margaret Tafoya" through Jan. 4. "Dinosaurs in Their Time" continues. 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 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 ages 2 to 18. Phipps members and children under 2 are admitted free. Call 412-622-6914 or visit www.phipps.conservatory.org.