click 'Line' and make a shape such as in Image 01 below..
 Image 01 
Next, click 'vertex', and then right click on the yellow point to edit the line (make smooth)
and a box will appear, then choose the 'Bezier' or 'Smooth'
another step, click 'Modifier List' and click 'Lathe'
Image 02 
DONE!! :)
If the dome not turn out like in Image 02, try to setting at the side bar.
change the output or else...
good luck!!..:)
to make a something better with this dome, try to build another shape, and combine.
Image 03
on the above image, i have put four pole, and make a floor and arrange like a stairs.
the last step, playing with material, make suitable with the building and add some lighting.
it will be nice try...:)
Insya_ALLAH 

 
 
