Complex sentence: Dedicated in 1928 and 1929, with each of the 12 located in a different state, they became a source of local pride, and, through the continuing efforts of local and national groups, all are currently in good condition and on display.
Split into simpler sentences: Dedicated in 1928 and 1929, with each of the 12 located in a different state, they became a source of local pride. Through the continuing efforts of local and national groups, all are currently in good condition and on display.