This is a 2000-2500 year old Thracian chariot with two skeletal horses attached! The Thracians were Indo-European peoples, living in Central and Southeastern Europe. This particular archeological dig site is located in modern-day Bulgaria.
Some exhumed burial mounds have contained chariots with as many as eight horses and even pet dogs! A mound was actually excavated recently in which the horses had been buried in an upright position!