In 2009, during my Asialink residency in Seoul, me and a bunch of others decided to make the journey to Muuido, an island near Incheon airport. Well, it seemed like it was 'near'.
We ended up on the beach at the top right of the map near Silmido. Couldn't get to Silmido itself because of the tides and warnings from ajummas not to cross the rock bridge ... which turned out to be wrong.
It's actually a nice place, lots of camping under pine trees, and not as many people as I thought there would be. Just no swimming. And no time to do anything.
Sounds great, huh?