Use that phrase for your search. You will come up with 17 pages of answers.
ok lets see
From FAQ:
Q: "What's underneath the Earth?" aka "What's on the bottom?" aka "What's on the other side?"
A: This is unknown. Some believe it to be just rocks, others believe the Earth rests on the back of four elephants and a turtle.
From search:
"The Reason by Nightwish11" - unanswered
"My questions by MrCrazyMc" - told read FAQ
"Skeptic Here by absimo613" - told read FAQ
"Re: Time Dilation by Robosteve" - says there might not be an other side
"Right, I've read the FAQ and that answered one question... by Tom Bishop" - says do'nt know
"Re: Question for FE by Dioptimus Drime" - says do'nt know
"Re: Can the Flat Earth Theory explain these counterpoints? by ItsRound" - says dirt
"Re: Dubious... by Curiously" - no answer
"Re: wait so site is joke right? by Raist" - says shadow object
"Re: gravity by wgzero" - says antimatter
"Re: So, tell me. by Saddam Hussein" - says God is hold earth up
"Re: Fly Real High by Saddam Hussein" - says exact copy of this side, rotated 180 degrees
"Re: Where is the south-pole? by RoboSteve" - says south magnetic pole
"A thought on the UA... by Unimportant" - says "stuff"
"if the earth is flat, then why...... by Nevyn" - says noone knows if there are people
"my theory by Northrider5" - says noone knows
"So What do people think is underneath our flat earth? by dysfunction" says basically we don't know
"If the earth is indeed flat.. then by Unimportant" - probably isn't much
"Space Station by midgard" - says something hidden that the conspiracy wants to keep secret
"Re: Origin of the conspiracy? by fshy94" - says something bad
not really a unified response
but if you not know it ok to say you dont know dont be afraid