I am not surprised the Rover filmed this pyramid from several miles away and in low resolution. The fact that these pyramids exist on Mars is probably well known to NASA due to Orbiter photos.
According to Streetcap1, the distance is about 7 to 8 miles away.
And what looks like a possible ancient sarcophagus or statue on Mars found in another recent Curiosity Rover image.
It looks like a priest with a rather elegant face with eye nose and chin visible showing a beaded headdress hanging down. The head looks small but the coffin is angled with the foot end closer.
Also some interesting details along the side of it with what looks to be a cross.
There also seems to be what looks like a carved cat or sphinx head with large ears pointing back and interesting face detail nearby along the ridge.
The sarcophagus looks to be between 5 and 7 feet long. The cat head around 1 – 2 feet wide.
This may well have been standing up like a statue at some point in the past.