Can an unaccompanied minor enter a foreign country?

i want to go to russia and possibly other european countries when i graduate high school, however i will only be 17 and wont turn 18 until november. Can I go alone or do i need someone 18 or older to travel with me? Will airlines treat me as an unaccompanied minor and assign me to a flight attendant like they do to 12 year olds? anything helps