Symmetry exists in architecture all around the world.  The best known example of this is the Taj Mahal.
 

In this view of the building there is a line of symmetry through the centre of the tomb from top to bottom.

It was completed in 1630 by the Indian ruler Shahs Jahan as a tomb for his favourite wife Mumtaz Mahal who died as a result of giving birth to their 14th child.

To build this tomb it took 20 000 workers, 20 years (Encarta 97) and it is rumoured that they used 40 000 elephants to transport the materials.
 

This photograph shows 2 lines of symmetry. One vertical, the other along the waterline. (Notice how the prayer towers, called minarets, are reflected in the water and side to side).