Complex sentence: North DeKalb Mall was originally built as an enclosed mall anchored by Rich's and a Woolworth's, the mall opened in 1965 providing the third major shopping center in the county in addition to Belvedere Plaza and Columbia Mall (later Avondale Mall).
Split into simpler sentences: North DeKalb Mall was originally built as an enclosed mall anchored by Rich's and a Woolworth's. The mall first opened in 1965, providing the third major shopping center in the county in addition to Belvedere Plaza and Columbia Mall (later Avondale Mall).