The science and cultural center is also issuing tickets for half-hour time blocks to more efficiently pace visitors through the exhibit on display at Salt Lake City's former Main Library until January.

"Tens of thousands of visitors have already attended Body Worlds [since its Sept. 19 opening], and we expect demand to continue to increase," said Alexandra Hesse, exhibits and programs director for The Leonardo.

"We are happy to extend our hours to ensure visitors have even more opportunities to experience this wonderful exhibit."

The show, Body Worlds 3 and the Story of the Heart, displays real human bodies that have been preserved sans skin through "plastination," a process that replaces fats and water in the tissue with polymers. Some two dozen full figures are staged in dynamic poses and dozens of other specimens reveal the circulatory and nervous systems, fetal development and disease processes in vital organs.

The new hours will make it easier for people to attend the exhibit after work, but ticketing procedures require visitors to get to old Main Library early or buy tickets in advance. You must buy your ticket before 5 p.m. Sunday through Wednesday, and 7 p.m. Thursday through Saturday.

Average "dwell time" for the show is 90 minutes, with bottlenecks occurring Friday and Saturday after 3 p.m. "The best times to come are early afternoon during the week," Leonardo spokesman Lisa Davis said.

"What you need to do is buy your ticket ahead if you want to go on a Friday evening. The problem is when you show up at 4 p.m. and haven't bought your ticket."

Leonardo officials on Friday declined to give precise attendance figures, citing contractual obligations with Body Worlds creators.

- Brian Maffly

Body Worlds 3 and the Story of the Heart

New hours » Sunday through Wednesday, through Jan. 11, 2009: 10 a.m. to 7 p.m. (tickets sold 9 a.m. to 5 p.m.) Thursday through Saturday: 10 a.m. to 9 p.m. (tickets sold 9 a.m. to 7 p.m.)

Where » Salt Lake City's former Main Library, 209 E. 500 South, Salt Lake City

For tickets and information » Go to The Leonardo box office, or visit www.theleonardo.org. For additional questions, call 801-220-1100.

Cost » $22 for adults, $16 for children, $19.50 for seniors. Online purchases are subject to a $2.50 per ticket service charge, but $2 discount coupons are widely available.