Some possibilities:

- You had a shared dream, this was another dreamer who you met. Scientific study of shared dreams is very young, and it hasn't been proven yet. But there are many DV members, including me, who can vouch for the possibility of shared dreams, and who have documented a shared dream. WakingNomad, Raven Knight, Walms, and Man Of Shred all regularly document shared dreams. Nobody blames you if you think its BS (trust me, even the shared dreamers sometimes wonder) but don't discount it.

- You saw it somewhere before, and forgot it.

- It was a huge coincidence-- Easter island is a well known place, and likely to popup in dreams, as are other places like the Eiffel tower, Empire State building, Area 51, and the Black Sea. The moon is also a place people like to meet up.