For the last 56 years, the Dolmen of Guadalpera has been submerged under the Valdecañas Reservoir in Spain, but after the record-breaking summer, two heat waves brought forth a drought that reduced the shoreline so much the megalithic stone circle was revealed on dry land again.

The monument is made of 150 granite stones, some of which are carved, placed in a vertical arrangement. The circle of stones creates an egg-shaped central chamber 5 meters (16.4 feet) across, preceded by an access corridor over four times the size in length.  At the entrance of the central chamber, a carved stone 2 meters (six feet) in height has markings that archaeologists believe represents the River Tagus, the river that was dammed to create the reservoir.

The tallest stone is usually just below the water surface, though over the last five decades (but particularly the last one) the monument has appeared in partial view. This summer, however, was the first time since 1963 that the entire monument emerged completely from the water.

Many parts of the northern hemisphere experienced droughts this summer. Spain suffered record-breaking temperatures early on in the season with above-average temperatures continuing into September. It is not surprising that June was the third-driest month the country has faced this century.

The drought badly impacted farmers as crops wilted and the reservoir got significantly drier. In images snapped by the Operational Land Imager on NASA' Earth observation satellite Landsat 8, the extent of the drought is particularly evident. The comparison between the same time and place in 2013 and in 2019 is stark.

The stone circle, also known as the "Spanish Stonehenge", was built about 7,000 years ago. It's thought it originally had a roof and might have served as a tomb, trading hub, or as a place to perform religious rituals. It was discovered by German archaeologist Hugo Obermaier in 1926. The Valdecañas Reservoir was built under Spain's Fascist dictator Francisco Franco in the 1960s.

The resurfacing of the stone circles has brought more interest in the monument and a group of locals has started a petition to have it moved away from the lake. The stones are granite and are porous, so being submerged for decades has taken its toll on them and people are worried that the monument will soon be gone, taking with it an important piece of prehistoric Spain.