What do think of mountain as a guess? Unofficial
If it’s a specific mountain I would think that it would probably be a landmark.
Well it’s big, unique, not man made and been around for at least 300 years. It’s also not a landmark. Would lake or river qualify? Rivers move but they river ‘usually’ stays in one place. Lake is more stationary.
I’d rather start by asking if it’s a body of water. That seems broader than asking about a mountain range. If it’s NOT a body of water, my next guess would have been about mountains, chasms (Grand Canyon, anyone?), etc.
oops, missed this. Yeah, I think a river stays in one place (mostly) even if the water in the river is moving.
Grand Canyon was my initial thought too, but I would definitely classify as a natural landmark. Twig may not though.
Yeah, I don’t have a good sense of what she would consider a landmark. But she’s been clear enough that her definition is fairly narrow that I am just ignoring that, and using the other answers.
If the Grand Canyon isn’t a national landmark than nothing is
Official: Is it a body of water, such as a lake, river, bay, etc.?
Oh and the Grand Canyon has a designation as a National Landmark, so it’s clearly not that.
The question was “natural”, not “national”. Still, I’d consider it a landmark, natural/national/whatever.
Further thoughts on landmarks. Imagine yourself having the following conversation:
A: Where are you?
B: I’m at [landmark].
A: OK, I’ll come pick you up in 20 minutes.
That works for Blue Grotto. It doesn’t work for Sahara Desert.
If that conversation would be ridiculously non-specific then I probably don’t consider it a landmark.
I mean, yes, maybe you need to clarify exactly which entrance or provide slight clarifying details, but A has a pretty good idea where on the planet B is.
If A said “I’m under the moon” or “I can see the moon” that would be no help at all… well, very little help anyway.
Well the Grand Canyon is natural. And the inter webs tell me it’s a landmark.
- John.S.Mill - Is it larger than a shoebox? Yes
- Celalta - Is it alive? No
- soyleche - Would you have been able to see it 300 years ago? Yes
- Lucy - Is it something that tends to stay put? Yes
- soyleche - Is it man-made? No
- Kat987 - Is it a natural landmark? No
- Lucy - Is it larger than a house? Yes
- Lucy - Is it unique? Yes
- soyleche - Is it located in the Americas? Yes
- Lucy - Is it a body of water such as a lake, river, bay, etc.? Yes
*Re: 4… see Lucy’s definition of “tends to stay put” that would be “yes” for cooking pot and oven and “no” for clothing and tent.
I don’t think it meets the “I’ll pick you up in 20 minutes” test.
It would certainly stretch it to the limit. The Grand Canyon is almost 2,000 square miles which just seems bigger than a “landmark” to me. I mean, that’s bigger than Rhode Island. I don’t think of Rhode Island as a landmark. 
The landmark question did give me pause, which is why I provided a definition.
Well if people wanna make their own definitions it makes it rough.
But we are down to water. Should we go with lake?
Maybe it could be one of the Great Lakes, Gulf of Mexico, Gulf of California, Great Salt Lake, Rio Grande, Mississippi River…
Americas so Canada, central and South America in play. But it’s unique so specific lake, bay, or river. Ocean would be tough to fit in but maybe.
Is it salt water?