This is obviously a primitive astronomical device created by Druids in the late Iron Age. You can see the two sets of 24 counting markers around the periphery, which were used to predict lunar eclipses. Two small four-legged devices (one seen just above the post at the bottom of the picture, the other having long disappeared) are the indicators moved from one marker to the next each year. At the end of 18 years the marker is moved each moonrise along the next 6 markers to account for the fact that the lunar cycle is 18.6 and not 18 years. When the 25th marker is reached a new cycle begins.

Also to be seen are the two triangular devices that mark summer and winter solstices, and the central gnomon, which shows the length of each day and the specific time.

The site is unique in that it includes a pile of tubes which were obviously intended to be used to create a true henge, left unfinished when the civilization mysteriously disappeared.

This beauty loomed over the heart of Fisherman's Wharf until around 1963. The site is now (what else) a motel.

This appears to be near the corner of West Jefferson and West Grand Boulevard. Today, just a vacant lot.

When I grew up in the 1950s we lived in cities that used coal gas. When you light a natural gas burner on your stove, it ignites fairly quietly. With coal gas there was a pronounced "POP" when lit. Natural gas has no odour so there is an additive (Mercaptan) to tell if there is a gas leak. Coal gas did not need an additive - it smelled like mothballs. Unburned coal gas was deadly, and some people committed suicide by inhaling it. Your nose told you when you were near a gasworks in your city. Several cities on the South Island of New Zealand still had coal gas generated as late as the 1980s.

North Attleborough, Mass., had a classy brick "gas house." From what I see online, brick structures protected the iron gasometers inside and extended their lives. North Attleborough's gas house survives and has been re-purposed as a home for several small businesses.