I visited London right after I read Neal Stephenson's Baroque Cycle, and we ended up in a cathedral off Fleet Street (I was quite disappointed that my mental image from the books was a 20m wide open sewer and in fact the buildings today might only be 5m apart close to the Thames) which was designed by Christopher Wren after the London Fire.

I don't recall the name, I'm sure someone here who knows London can work it out from my description, but you could go up into the dome and I remarked to myself that the fall to the marble floor from the highest opening in the dome could easily kill a man.

I've probably repeated this story here half a dozen times now, but in the background information posted at the church it said that he had so many people wanting to commission him for building their church yesterday that he built them without bell towers with an agreement that once everyone was back in business, he'd come back around and build the towers on. Seeing how complex those domes were, I'm not quite clear why adding a tower later was a substantial savings in time and effort but that's the story.