There - talking about a place usually.. (The Spartans are over there) Their - shows possession of something.. (The Spartans carry their weapons with pride) They're - honestly the most confusing version, but actually a conjunction for "they are".. (I love Spartans, they're awesome!).. ((If you can replace this version of there/their/they're with "they are", then you know for sure it is "they're")) ;)