Visitors will learn about the Ferris wheel, boating lake, dance pavilion and Louis Armstrong at 7 p.m. Thursday at Alameda Park.

A slide show of rare photographs, video clips and tales will be part of the Butler County Parks and Recreation Department Outdoor Discovery program.

Admission is free.

SLIPPERY ROCK — All types of reading material will be for sale during the Slippery Rock Community Library Annual Book Sale.The preview sale will be from 5 to 8 p.m. Friday, and there is an entry fee.The sale will continue from 9 a.m. to 3 p.m. Saturday without an entry fee. A bag sale will start at 1 p.m.All proceeds support operations of the Slippery Rock Community Library.Book donations will be accepted until Thursday at the library, 316 N. Main St., Slippery Rock.Call 724-738-9179 for more information.

Bill May of Butler will present “Gettysburg — The Stories Behind the Monuments,” a 60-minute slide show and talk, at the Butler County Civil War Roundtable scheduled at 7 p.m. June 26 at the Butler YWCA, 120 W. Cunningham St.The Battle of Gettysburg was fought 150 years ago on July 1 to 3, 1863.May will tell the hidden stories of the Battle of Gettysburg that the soldiers wanted told through their monuments at Gettysburg.