” In another moment down went Alice after it, never once considering how in the world she was to get out again. The rabbit–hole went straight on like a tunnel for some way, and then dipped suddenly down, so suddenly that Alice had not a moment to think about stopping herself before she found herself falling down a very deep well.”
http://etc.usf.edu/lit2go/1/alices-adventures-in-wonderland/1/chapter-i-down-the-rabbit-hole/