JUDY WOODRUFF: Parts of Europe baked in out-of-the-ordinary warm spells this summer. But as the NewsHour's Julia Griffin reports, while uncomfortable for some, the heat revealed a treasure trove of long-lost historical landmarks.
JULIA GRIFFIN: In the United Kingdom and Ireland this summer, prolonged heat waves sent city residents in search of shade and cooling spritzes.
WOMAN: It's way too hot, and people aren't used to it.
JULIA GRIFFIN: And prompted dairy farmers to ration feed.
ABI READER, Dairy Farmer: I haven't seen the farm this dry ever. I think the last time we had a very dry period on the farm was in 1976.
JULIA GRIFFIN: But while trying for some, the British Isles' driest summer in 57 years has been a boon for local archaeologists and history buffs.
ANTHONY MURPHY, Photographer, Mythical Ireland: It's been tremendously exciting.
JULIA GRIFFIN: In July, author Anthony Murphy photographed a 5,000-year-old previously undiscovered gathering site known as a henge in Eastern Ireland.
ANTHONY MURPHY: I just simply couldn't believe what I was seeing. This was in a field of crops. So this wasn't the marks of farm machinery in the soil or anything.
JULIA GRIFFIN: Instead, the concentric rings of dots were crop marks, ghostly outlines of a civilization past emerging from the moisture-starved landscape. Crop marks and their related phenomena, parch marks, allow drone operators and aerial archaeologist to see thousands of years of history beneath the dry soil without ever having to pick up a shovel. Here's why they form. Over time, prehistoric ditches, moats and other dug-out features are filled in by subsequent generations. Today, those areas retain more water and dry spells than the surrounding earth and lead to taller and greener grasses and crops. At the same time, thin layers of soil placed over old stone walls or building foundations cause vegetation above to dry out more quickly. The result is a variety of geometric figures visible only from above.
DAMIAN GRADY, Historic England: We discovered hundreds of new sites this year spanning about 6,000 years England's history. Damian Grady is an aerial reconnaissance manager with Historic England, one of them many groups chronicling the sites for future preservation and excavation.
DAMIAN GRADY: These range from Neolithic ceremonial monuments, Iron Age, Bronze Age and Roman farms, medieval settlements in the east of England, and also World War II camps that we have not seen for a long time.
JULIA GRIFFIN: Among the group's older discoveries, a circular ditch associated with an Iron Age settlement known as a round, the enclosed fields and paddocks of a Roman era farm, and an unusual triple-ditched burial mound likely from the Bronze Age. But there have also been rediscoveries of more recent activity, like the long-gone barracks and sidewalks of a World War I prisoner of war camp in Southern Scotland, the foundations of Tixall Hall in Staffordshire, England where Mary Queen of Scots was once imprisoned, and the geometric pattern of an 1850s garden etched once again in the grounds of Gawthorpe Hall in Lancashire, England. Rising temperatures are revealing secrets across the English Channel too. In Switzerland, researchers have announced the discovery of the C-53 Dakota aircraft. It had crash-landed on a glacier in the Bernese Alps in 1946.
NARRATOR: This is the forbidding seen high up in the Bernese Overland where the now famous Dakota came down.
JULIA GRIFFIN: All 12 people aboard the U.S. Army transport plane survived the ordeal, but for five frigid days, they were forced to live only on melted snow and rationed chocolate as they awaited rescue. Newsreel footage from the time chronicled how Swiss pilots used reconnaissance planes fitted with skis to bury the passengers to safety two by two.
NARRATOR: As for the reunions, well, they certainly were good to see.
JULIA GRIFFIN: The event marks the first time the Swiss Air Force used planes for a mountain rescue. Since then, the Dakota was locked away, frozen under layers of snow and ice, until the summer, when heat waves and the glaciers' retreat revealed the wreckage once again, about two miles down from the original crash site. Archaeologists and the Swiss Air Force are working to retrieve the wreckage and hope one day to put its artifacts on display. For the PBS NewsHour, I'm Julia Griffin.
1.live on 靠....生活
I live on an invalidity pension.
2.be used to 适应
I didn't think I could ever get used to living in a big city after living in the country.
For me it was like meeting a long-lost sister. We talked, and talked, and talked
对我来说就像久别的姐妹重逢一样 。我们聊呀聊呀，话总是说不完 。
4.emerge from 浮现
His voice stopped short as he saw the blade emerge from Desmond's pocket.
5.range from 从...变化
Madagascar's ecosystems range from rainforest to semi-desert.
安东尼·墨菲：我简直不敢相信自己看到了什么。这里是一片庄稼地 。所以肯定不是农业机械或者类似事物的标志 。
茱莉亚·格里芬：这些同轴点环是作物标志，仿佛勾勒出了过往的闻名，让其缓缓从干旱的土地上浮现。 作物标志等相关的景象（比如烘烤的标志）都让无人机的操作者和考古学家得以在不用费力刨地的情况下，看到干旱土壤之下数千年的历史 。他们的形成原因是：随着时间的流逝，史前的水道、壕沟等地下掩蔽特征都因子孙后代的活动而被填满 。如今，这片土地上的含水量更多，干旱期也比周围的地貌更久，所以草和庄稼长得更高、更绿 。与此同时，古老石墙和地基之上的层层薄土让农作物干的更快 。所以，很多几何形状只能从上方可见 。
达米安·格雷迪，英格兰历史：今年，我们发现了上百出新遗址，跨度在英国历史的近6000年左右。达米安·格雷迪是《英格兰历史》的空中侦察经理 。《英格兰历史》这样的机构还有很多，他们的存在都是为了确定遗址的时间，以便日后进行保护和出土 。
茱莉亚·格里芬：所发现的遗址中一些年头比较久远有：铁器时代的密闭圆形壕沟、罗马农场的小牧场、很可能源自铜器时代某三处壕沟入口的罕见古陵。也有较近时期的，比如苏格兰南部某一战战俘营的营房和人行道、斯塔福德郡Tixall Hall的地基 。当年，苏格兰的玛丽女王曾囚禁于此 。此外还有19世纪50年代的几何图案，后来又在英格兰兰开夏郡Gawthorpe Hall的地下经过了一番蚀刻 。升温也揭开了英吉利海峡的许多秘密 。瑞士的一些研究人员宣布他们发现了C-53达科达飞机 。1946年，该飞机在坠机后在伯恩阿尔卑斯山脉的冰川上着落 。
茱莉亚·格里芬：这次事件是瑞士空军首次动用飞机来进行山区内的营救。从那时起，达科达被困在皑皑冰雪之下，直到夏天来临，热浪让冰河融化才得以现出达科达的残骸 。其残骸距离失事处大概2英里 。考古学家和瑞士空军正在努力将残骸取出，以期有一天能将其进行展览 。感谢收听公共广播公司茱莉亚·格里芬为您发回的报道 。