Drawing Large buildings

Say for example you want to sketch a large building.  Lets face it, when we are sketching on our travels, we often look up at large buildings, so this is how I go about drawing them.

I think in terms of Shape     as with this photograph - (I have mentioned Shapes before here).

AND THAT'S THE KEY TO LOOKING UP

AND SKETCHING SOME BUILDINGS -

 THE PERSPECTIVE ELEMENT

LARGER AT THE BOTTOM

TAPERING SMALLER TOWARDS THE 

TOP

a TRIANGLE

Makes sketching much easier when you keep this principle in mind