Maya model in unity help

i built a dome in Maya 2011 but the problem is i can see the through the walls when i walk in to the dome

Sorry really tired to try to explain it but take a look
at this url and you will see whats wrong

http://letsallplaygames.com/unity/mars.html

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It’s because backfaces are being culled.

See here http://forum.unity3d.com/viewtopic.php?p=191526