Expanding on the last post, here are lots of pictures of stone walls, loosely mortared together with rambling commentary.
These two are from buildings in Ollantaytambo. The old town is mostly as it was in Inca times, with narrow cobbled streets. The old buildings typically have a single storey, with monumental stone walls about ten feet high. On top of that is either adobe or modern brickwork, and occasionally a thatched roof (but, more often, tiles or corrugated iron).
We were admiring one of these walls when a woman came out of the house and invited us in to see their guinea pigs (definitely food not pets) and buy souvenirs. Susan came away with a rather lovely miniature silver llama for S/30, so everybody was happy with that deal. Note the double door jamb: this often means that the door was to somewhere important.
These are repeated from the last post: two closeups of extremely fine work on the Temple of the Sun in Ollantaytambo, where you really couldn't get a razor blade between the stones, and one from a terrace there, which actually shows that quite a lot of shaping work has been done rather than just throwing raw fieldstones together to make a wall.
This set shows some more parts of the Ollantaytambo fortress. First is an oblique view of the Wall of the Six Monoliths: identical 50-ton slabs that have been fitted together perfectly. Next is a drainage channel in one of the terraces (presumably a less important one, as the stonework's much rougher). Finally, we have the "bath of the princess" - a ceremonial fountain with some rather nice carving.
We now move on to Wiñay Wayna, a few hours' walk before Machu Picchu on the Inca Trail. The first two pictures are from the Temple of the Rainbow. It's not clear whether the name comes from the fact that it has seven windows, or that stones of slightly different shades seem to have been chosen for different areas of the wall. Our guide said that it was both, but the first one seems very suspicious to me: the rainbow was definitely very important to the Incas, but I thought that Western tradition only holds that it has seven colours because Newton thought it should match the days of the week, the objects in the solar system, and the notes in an octave. It seems surprising that the Incas should independently come up with the same number.
While we're off on a tangent about rainbows, you should be aware of the difference between the seven-striped flag of Cusco and indigenous Andeans, and the (usually six-striped) LGBT pride flag. There are not as many gay bars in Peru as a naive observer might think.
The third wall is just a wall that I thought looked nice - probably part of the agricultural terracing, and so is just fieldstones set in mortar. The stones in the temple walls are dressed and laid in courses, but not as finely worked as the houses in Ollantaytambo, despite being part of a temple.
These are from Intipunku, the Sun Gate of Machu Picchu. It was probably the final military checkpoint on the way from Cusco, and it's the final landmark (as well as the end of walking uphill) on the Inca Trail. Viewed from Machu Picchu, the rising sun passes through it on the summer solstice. These walls aren't part of the main gate, which looks like it's been extensively restored, but would have been part of nearby buildings, perhaps a guardhouse. I rather like the enormous boulder.
At Machu Picchu itself, there's a very visible difference between the important religious sites and the rest of the sanctuary. Here's a representative bit of terracing, and two closeups of one of the terrace walls. I'm struck by how much more informal these are than the terraces at Ollantaytambo, where quite a lot of work has gone in to shaping some of the bigger stones.
The Temple of the Sun stands out for just how carefully everything was finished, although it's still not quite as perfect to my eye as the work on the temple in Ollantaytambo. The big gaps on the first picture are because the blocks have shifted during earthquakes in the last 500 years.
There are lots of interesting anti-seismic techniques in ancient Peruvian architecture: the Moche were building enormous temples out of loosely-coupled stacks of adobe bricks almost two thousand years ago, but I'm getting ahead of myself. For now, let's just note how most of the doorways and windows are trapezoidal, and how it's common to see walls that are quite a lot thicker at the bottom.
Here's some more sacred architecture from Machu Picchu: the main temple, the Temple of Three Windows (well, two of them), and the Intihuatana, carved from the mountain to point straight at the sun at the solstices. It's hard to get a sense of scale here, but the big stone between the two windows is at least two metres on each side.
A lot of the finer Inca stonework is impressive for the number of angles that get fitted together perfectly. There's a twelve-angled stone on a street in Cusco that's almost impossible to walk past, day or night, because of the crowds of people taking selfies. Much of colonial Cusco is built from Inca stone taken from the hilltop fortress of Sacsayhuamán by the Spaniards. There are still three enormous terrace walls there, probably because the stones (the largest are estimated to weigh up to 200 tons) were too heavy to be moved.
Sacsayhuamán has one feature I haven't seen elsewhere: enormous stones that have been carved to go around the inside of corners:
Finally, here's a view from beneath Sacsayhuamán's Intipunku: those little steps there are at least normal size, if not larger.