I just spent a couple of weekends drawing the church of Saint Eustache in the centre of Paris. I was impressed by this view with the differnet volumes and asymmetry. The photos below show a progression from pencil preparatory drawing on 6 sheets of A4 cartridge glued together, through to the finished pen drawing. I used a Unipin 0.5mm and I rubbed out the initial pencil lines afterwards. 

Here's the pencil draft showing some rectifications :

The following day I started going over it with the fineliner :

It was important to take photos at the start because the shadows changed a lot in the time I was there :
 

 

Here's a close-up. And no I'm not left-handed :)

Another close-up. Building up the ink drawing and some shading/cross-hatching :

The weather stayed dry thankfully :

This is where I got to on the end of the second day :
 

The third day :

And the fourth day :

Nearing completion :

A close-up :

Here I've rubbed out the pencil lines :