Cemeteries are of prime interest to genealogists and family researchers for the amount of family information they may contain. Graves are often marked with headstones (also known as tombstones or grave markers) or other memorials that provide information about the person buried such as the date of death, the date or year of birth, and other family information. One may find other family members buried nearby, perhaps in family plots. In addtion to headstones, most cemeteries have a sexton who maintains a record of burials. Where cemeteries are privately owned such as old family cemeteries on private land, it may be necessary to obtain permission to visit. Also, some cemeteries prohibit certain research activities such as making rubbings of headstones. Due their general isolation, cemeteries are places to exercise caution. It's best to go in the company of others and to lock your vehicle.