Whenever you want to travel to a kind of amusement park, but still want a quite place, visit Ecoland in Jeju Iland, Korea.
You can feel you are alive by looking around here.
You can meet some kinds of different themes while taking the yellow train below. Whenever you want to stop and take some photos there, you can get off from that train and hang out there. If you want to visit the other theme, then you can again jump up to the train and go to next train station.
There are 5 train station, which are 'main', 'eco-bridge', 'lakeside', 'picnic garden', and 'Lavendar/Greentea & Rose garden'.
You can buy the ticket to enter this Ecoland. The ticket costs around 12,000KRW (around $11) but you can enjoy the whole day by hanging around here Ecoland! What a cost-effectiveness invest :)
(It looks like I am advertising here, but seriously I am not sponsored by anyone.)
However, these days it is winter season in Korea, so that the entrance fee is cheaper than it of spring season.
You can get 25% discount on the ticket if you make reservation on the below web-site.