Right after I got to Istanbul on this most recent trip, I took a taxi from my hotel down to the Bosphorus, to check out the Rumeli Hisarı, a fort complex built in 1452 by Sultan Mehmet the II in anticipation of the following year’s siege of Constantinople. It’s constructed at the narrowest point on the Bosphorus (660 m wide), with the aim of controlling boat traffic coming from the Black Sea. This narrow spot is today where they have the second of two bridges spanning the Bosphorus. It looks like this:

It’s in Europe; that’s Asia on the far right of the photo. A few more shots of the fortress’s pattern of towers and interconnecting walls:

Inside, I was pleased to note the variety of building stones. Here’s a nice porphyritic andesite which was a common constituent of the walls:

And a folded limestone:

Here are some yellowish blocks that are weathering away faster than the mortar which holds them in place. There is a Turkish 1-lira coin in front of the dark block near the center, to provide a sense of scale:

Here’s a similar phenomenon playing out with some bricks used to make an archway, except here the mortar is the more rapidly weathering component:

Check out this slab of brick… it’s got a curious adornment:

Zoomed in to show this detail:

Dog prints! Sometime a long time ago, maybe more than 500 years ago, a brick maker put out slabs of clay to dry, and some long-dead dog walked across it. The dog’s footprints are a kind of “historical trace fossil” that was then incorporated into this ancient structure.

Visiting the Rumeli Hisarı was a pleasant experience. I walked down along the Bosphorus next, peering into its surprisingly clear waters and counting jellyfish, then got a pide at a cafe. I caught another cab back to the hotel, and eventually fell asleep, a victim of jet lag…