The Pantheon of National Revival Heroes is a national museum-ossuary, erected in memory of the Bulgarians who gave their lives for the liberation of Bulgaria. It contains the bones of 453 revolutionaries and volunteers who participated in the Russo-Turkish War of 1877-1878, rebels, and other social activists. Among them are Lyuben Karavelov, Zahari Stoyanov, Toma Kardzhiev, and Olimpi Panov. A tribute is also paid to Baba Tonka and the Obretenov family. The Pantheon was opened in 1978 on the occasion of the celebrations of a century since the liberation of Bulgaria. It also includes a museum exhibition and a chapel.