Napsugár Erdő
Description
The Sunshine Forest is a somewhat dense forest that is dotted with multiple shrubs and bushes with multiple clearings. The trees reach several meters tall, though one can easily see through its canopy.
The dungeon's safe area consists of multiple layers of cobblestone walls with a plot of grass atop each layer. It can be inferred that this safe area rather consists of a run down temple.
Chronology
Aincrad Arc
Red-nosed Reindeer
After Kirito joins the Moonlit Black Cats, he is later shown in this dungeon fighting a Killer Mantis. After Sachi becomes startled by the monster's intimidating appearance, Kirito switches out with her. After cutting off a scythe-arm and deflecting the other, he calls out to «switch» with Tetsuo, who then finishes the monster off.
The guild members then rest in the safe area, where Keita wonders about the leading clearers on the 28th floor. The rest of the group joke with Keita about his dream in that his guild would soon be among the front lines, to which Keita responds with that it isn't wrong to dream big, and that the next goal would be that everyone will reach Level 30.