The historic city of Tula was founded in the 14th century. The downtown (or "center") is a pleasant place for a stroll.
Located just up the hill from downtown Tula, Vsekhsvyatsky Cathedral is worth seeing - as is its accompanying cemetery.
Despite the Western view that "kremlin" is a word solely associated with Moscow, the word translates as fortresss. Centuries ago, all Russian cities had a central, walled kremlin.