The Inca Ruins of Machu Picchu, Peru

I just had one of my best days ever at Machu Picchu, Peru. Sunshine in the morning on the train ride from Urubamba, a developing cell of moisture signaling the beginning of the rainy season, and clearing by evening. But I get ahead of myself.

There is a reason that the highway ends at Ollantaytambo. The Urubamba River flows past the softer sedimentary and volcanic rocks of its upper valley and then encounters resistant granite belonging to the Vicabamba batholith. Quite suddenly, the riverside fields of corn and quinoa give way to massive depsosits of river debris, now being dissected by the huge runoff that occurs here in the rainy season. House size boulders tumble from the walls of these deposits and make the Urubamba one angry stream.

Looking back upstream from the train near the head of the gorge. Note the cliff face of loose, unconsolidated river debris now being dissected by the river. This debris chokes the channel and makes the river fall with great force. The Urubamba is a large tributary of the Amazon River and is here about 8,000 feet above sea level.

I have been here in the heart of the rainy season and seen the river filled bank to bank with runoff. At this time of year at the start of the season, it is but a semblance of its potential glory.

This looks like a fairly recent cut on the left bank, exposing some huge boulders that are now on their way to the Amazon Basin.

Note the vegetation here of cactus and scrub.

But in a few miles - literally, the Amazon forest creeps up into the gorge from lower elevations.

Nearing the end of the train ride.

The batholith is well exposed as we begin the bus ride up to the ruins - 2,000 feet above the river in fourteen cliff-hanging switchbacks. The granite was intruded into the South American crust about 277 million years ago, in the Permian. (Coincidentally, this makes this granite the same age as the Schnebly Hill Formation in Sedona).

Here is a view of the switchbacks (from a previous trip) from the river to the ruins, located on a slope of Machu Picchu Mountain.

Our group! Wonderful travel mates and friends of the Smithsonian.

Clouds began to build across the way but the ruins are still in the sun.

Some of the gabled roof residences of the former inhabitants.

The Inca were masters at controlling their water use and carved ornate pathways for water to run through their complexes.

Looking out from a reconstructed habitation site. Machu Picchu was built around 1450 by Pachacuti.

Carved bedrock beneath the Temple of the Sun.

Bedrock infilled with cut stones.

View of the Temple of the Sun with Huyna Picchu behind.

The ornate doorway used by Pachacuti between the temple and his residence.

Temple of the Sun.

The rain begins. I wil have more from Machu Picchu tomorrow and thanks for reading.