I do not know if those things are artificial or natural, Nature can make some strange things, even human beings.
What I do not like is people showing some photos and telling me what I must see, like when they say that the picture shows a fort, a house, a cow,
George Bush, Bin Ladden, etc.
Those people, maybe without knowing it, are forcing the others to make a decision, in favour or against what they are saying, and after that they get
angry against the people that do not see in those pictures what they see.
Its like looking at the clouds, our brain does the interpretation, if something does not look obviously like a known object, different people will see
different things, like in a Rorschach test.
Here on Earth we have some strange features on the surface of the planet, but we can only really see the surface on the deserts and places like that,
where the vegetation does not hide the real surface.
Some places I found:
Australia:
I suppose those walls are natural, but they look like they could have been artificially made.
Australia 1
Those triangles can also be seen as artificial.
Australia 2
Mexico:
The crater almost at the centre of the picture reminds me of some Mars photos.
Mexico
Niger:
I do not know what to think of this image, its so strange.
Niger 1
This looks like the remnants of a volcano.
Niger 2
USA:
Some of the features in this photo remind of the Mars photo with the ´T´ shaped thing.
St. Helen
Another crater similar to some of the Mars photos.
Amboy 1
A lava field is a strange thing, here or on Mars.
Amboy 2
Meteor Crater looks like an octagonal crater in this photo, not a round one.
Meteor Crater
My conclusion:
We do not know enough of our own planet, but we think we know enough about one millions of miles away, where we never set our feet, to start making
statements.
The Europeans took centuries to know what was on the other side of the Atlantic Ocean (some are still trying to understand what happens there
), why
must we know all about Mars in just some decades?
I would like to know if there is life on Mars, and what kind of live, and a lot of other things, but I think that this is something that only future
generations will know.
PS:I could spend the rest of my life just looking at sattelite photos.
*sighs* 
CD-ROMs they have there with the
pictures in the original format they used. 
