December 22, 2023

El Torcal karst and Antequera, Spain

Whilst in Andalusia in southern Spain, I did a tour to El Torcal and Antequera. El Torcal, or Sierra del Torcal, is a small mountain range south of Antequera in the province of Malaga.


It is a karst area known for its flat limestone blocks. The Jurassic limestone is about 150 myo and was laid down in a marine corridor along this section of the Spanish coast, from Malaga to Alicante (to the east). The seabeds were then uplifted to over 1300 m in the Tertiary era, during the Alpine orogeny. Unusually the resulting beds are quite flat. It is considered one of the most impressive karst landscapes in Europe. 


It almost looks man made, as if some giant hands have sculptured the landscape. The area was designated a Natural Site of National Interest in July 1929, and became a Natural Park Reserve in October 1978. And it is part of a UNESCO World Heritage site, along with the Antequera Dolmens Site and La Peña de los Enamorados or Lover's Rock.

Driving north from Malaga, the landscape is mostly gentle hills with very dry lands. As you approach El Torcal you see the lighter coloured creamy rocks forming large hills or small mountains. The road goes up to the visitors' centre. We had no time to look in here, instead walked straight to the viewpoint. This was being renovated and unfortunately the view was right into the sun. However around the path you get a good view of the flat lying limestone. Rocks looked like they had been piled on top of others, just like the small stacks of rocks people now build in tourist areas.



These features have been formed over the millennia when a series of fractures, cracks and faults at right angles were eroded, producing "alleys" between the limestone blocks. The blocks themselves have been subjected to both dissolution by water (karstification) and freeze-thaw splitting action which, working on the limestone's horizontal beds, resulted in the various shapes visible today. And of course many of these have been likened to things people see and have been given names such as the Sphinx, the Jug, the Camel, the Screw, etc.

The Screw is now used as the symbol of the park. From the car park we walked to see the Screw. On the way we were lucky enough to see a group of Spanish ibex, also known as the Andalusian mountain goat, the Iberian ibex, the Spanish wild goat and Iberian wild goat. This is a species of ibex, (Capra pyrenaica) that is endemic to the Iberian Peninsula. I was excited to see this first one standing on rocks at quite a distance. Then as we walked on, we saw a lot more -







There is a clear path with gravel most of the way though for some sections you are walking on limestone pavement. It was a pleasant walk to see The Screw.




We also saw some Griffon vultures but I didn't get any photos. There are also caves in the Torcal includes caves, although we didn't see any. Some of them are of historical importance like the Cueva del Toro (Cave of the Bull) with its Neolithic artifacts.

We then drove down through the valleys to Antequera. North of the town is Lovers' Rock, La Peña de los Enamorados. 



This rock, along with the dolmens, completes the World Heritage site. We didn't have time to visit the dolmens. There are three megalithic monuments: the Menga and Viera dolmens and the Tholos of El Romeral. 

"Built during the Neolithic and Bronze Age out of large stone blocks, these monuments form chambers with lintelled roofs or false cupolas. These three tombs, buried beneath their original earth tumuli, are one of the most remarkable architectural works of European prehistory and one of the most important examples of European Megalithism." (from Antequera Dolmens Site )

Apparently the entrance to Menga dolmen faces Lovers' Rock, so is the only dolmen in continental Europe that faces towards an anthropomorphic mountain. And Tholos of El Romeral, faces the El Torcal mountain range

In the centre of this photo is a brown chimney and in front of that is a grassy mound, that is one of the dolmens -


The World Heritage Antequera Dolmens Site was inscribed in 2016.

See more on Peña de los Enamorados ("The Lovers' Rock") on Wikipedia

November 22, 2023

Exeter - Hollow Earth: Art, Caves and the Subterranean Imaginary

 An exhibition at the Royal Albert Memorial Museum in Exeter in Devon, entitled "Hollow Earth: Art, Caves and the Subterranean Imaginary" is on until Jan 2024.


It shows how artists have portrayed caves over the years, so is not really an exhibition on caves, but different art forms. However there are some displays of animal bones found in caves, as Devon was one of the areas of early cave studies and contains important prehistoric cave deposits. William Pengelly was one of the pioneer researchers.

The exhibition is divided into five sections in two rooms and has works by more than 30 artists. I am not an artistic or creative person, so many of the exhibits were rather meaningless to me. I did like the old photos of researchers at various rock art.


There was a short contemporary film set in and around Thor's Cave in the Peak District, Derbyshire.  The film, "Echoes from the Void", by Michael Ho considers the cave as a kind of echo chamber and draws on imagery borrowed from Chinese myth and folklore. "Ho explains that the film, ‘re-examines the children’s game of ‘Chinese whispers’ within the context of the COVID-19 pandemic and the age of digital media. It seeks to discuss the East Asian diaspora as well as notions of cultural mismatch through the exposure of the mechanisms in which mis- and disinformation are produced, disseminated and consumed" - from Exeter Chamber.

There is a much longer, 46 minute, film in the other room, by Lydia Ourahmane. Made in 2022 at UNESCO World Heritage Site of Tassili n’Ajjer in the Sahara Desert, which is home to one of the most important groups of prehistoric rock art in the world, dating back to 12,000 BCE. The real scenery is stunning but I couldn't appreciate how it was filmed using low light levels and jerky out of focus shots, with many minutes of the camera "flying" just above ground level which could make some people feel "seasick". From Exeter Chamber "Describing the transformation of life in the region over thousands of years, Ourahmane’s commissioned film installation depicts otherworldly images of demons, extra- terrestrials and lost rivers. The first time Ourahmane visited, there were three water sources; now there is only one. Soon there may be none, and it will be almost impossible to travel there. Ourahmane described this ambitious journey as ‘an act of translation, an experiment of what we might unearth together’. The wordless film features an ‘exquisite corpse’-style soundtrack, composed by four musicians.



The wall mounted screen seen in the photo above was showing a film on the seed vault in Svalbard in Arctic Norway. This was of interest to me as I saw the outside of the seed bank less than 5 months ago in June 2023 -



The exhibition is free to visit. You can read a lot more detail about the art on the RAMM page and also Exeter Chamber

October 22, 2023

Underground London - Barnet Physic Well

Barnet’s Physic Well is a mineral water spring which was thought to have therapeutic qualities. The well was found in the 17th century and in 1656 the parish had a well house built. It was popular through to the 1820s, and its visitors included Samuel Pepys, who wrote about the visit in his diary. And nowadays they have open days, so I went for a look.

Barnet is in northwest London and the well is in what was Barnet Common, which is close to the hospital


In 1808 the well was rebuilt with a subterranean arched chamber. However it soon lost popularity and the building removed in 1840. The well was rediscovered in 1920 and in 1937 a Tudor-style building was erected by the Council. That fell into disrepair but was restored in 2018.  





Although the building has been restored, the steps and well room are original, now Grade I listed.


The well is just a small open tank. We were told the water level is always constant and the same temperature.



It was fashionable to drink the water at the time of Pepys. It acts as a diuretic, which makes the drinker urinate, and this was supposed to restore the body's balance. Pepys apparently drank several glasses on his first visit and had to stop several times on the way home! On another visit, he drank less of the water.

The water was so popular it was bottled and sold in London and Barnet was almost a spa town.  

A postcard with info on the well -



There is a display of clay pipes and horseshoes -



See more about the well on Barnet Common and Physic Well and also on the Barnet Museum page, which includes a 1976 bulletin on the well. 

August 15, 2023

Underground London - Brunel tunnel shaft

The first tunnel under the River Thames in London was also the first tunnel built under a navigable river anywhere in the world. It is the Thames Tunnel, and connects Rotherhithe on the south bank to Wapping on the north side. The tunnel was designed by Marc Brunel and his son Isambard Kingdom. It was opened in 1843.



Next to the Brunel Museum is a shaft that led down to the tunnel. This was open to visitors in August 2023. It is a large circular shaft and a modern staircase takes you down to the concrete floor. Some metres below, is the London Overground railway running through the Thames Tunnel - see map.



Looking up at the ceiling -


The tunnel originally 


It was quite an achievement building a tunnel in soft ground under a navigable river. In 1825 it was the busiest river in the world and because of the height of tall ships, a bridge wasn't feasible. So Marc Brunel had the idea to build a tunnel, and Isambard, aged 19, was the chief engineer. The tunnel shaft was built above ground and then sunk like a cookie cutter, with added bricks to weigh it down. It was made of two 25 ton iron hoops surrounded by bricks and rubble. It extended 12 m underground and provided access for the miners to dig out the tunnel, being protected by a Great Shield. They lined the tunnel with bricks.

It would have been a horrible job, being showered with water from the Thames which in those days was like a sewer. They worked in 2 hour shifts. In 1827 water flooded in and construction had to stop. The tunnel was finished in 1843, having taken 18 years to build rather than the expected 3. 

Once opened it became a huge tourist attraction, as people were fascinated by being able to walk under a river. There was even a fairground in 1852. In the late 1850s the tunnel was sold to the railways and Victorian steam trains used it. 


Outside is the engine house. It was built to house a boiler. This delivered steam to a pumping engine which pumped water out of the tunnel. The building now houses the museum.







The Thames with the tunnel below



Artwork by a local school -


And a poster in Rotherhithe station -


The Brunel family burial site in Kensal Green cemetery which I visited in 2020.


August 7, 2023

Guano collection from London Underground bridges

Collecting pigeon guano from special built dovecotes on railway bridges is a new concept. Pigeons have become somewhat of a pest in cities everywhere and are thriving. They are commonly called flying rats. However like the rest of us, they are only trying to survive.

A temporary exhibition in London's Design Museum is called "Islands. Design Researchers in Residence" and one of the sectors is called Dovecote for London



In the display, the exhibitor proposes a design for dovecotes, as a home for pigeons. These could be placed on railway bridges and the guano collected from inside could be used as a fertiliser for urban farms around London. This would benefit urban agriculture. 



Many years ago, some of the Pacific Islands were famous for the export of guano. This was used for fertilizers and explosives. One of the main islands was Nauru. This has even featured on several of their stamps -



A map of the Guano Line -


The dovecotes could house many pigeons and protect them from predators and the weather. They would have perches and entrances designed for pigeons.  A model of the inside of a dovecote -

I think it is a great idea and hope it actually happens.