Saturday, August 11, 2018

Recycled Hamburg flak towers

During World War II, the Nazis built so called Flak Towers -- fortified air defence bunkers -- in three cities, Berlin, Vienna, and Hamburg. I had previously been in the Thumboldthain tower in Berlin. Now I was able to visit two similar bunkers in Hamburg.

Whereas the Berlin bunker has been partially blown up, the Hamburg bunkers are in much better condition. One acts as a music school, media business park, and hosts shops.

The other one has was demolished internally with six of the eight floors collapsed, but has since then been renovated. This bunker acts today as a solar cell platform and buffer storage for renewable energy. Two million litres of water are used to store energy generated on the site, drawn from the solar cells, or waste heat from nearby industries. At the top the <vju> Café opens up for guests three days a week to look at the views and enjoy coffee.

The first bunker, Heiligengeistfeld Flak Tower is at the Heiligengeistfeld park in the center of Hamburg (N 53.55667 E 9.97036). The second bunker, the Energy Bunker is at Wilhelmsburg in the suburbs (N 53.50999, 9.98941). More information about the flak towers in general can be found from the wikipedia page.

I have mixed feelings about the bunkers. On one hand, they were a part of the German war machine, and the horrors of war are still all too present in their dark insides. But on the other hand, these bunkers are also interesting structures from an engineer perspective, and their current use is in stark contrast to the evil war times: teaching people about music or providing alternate energy sources.

There were beautiful concrete cuts... imagine having to slice through several meters of concrete to make a new door

I loved the painted concrete walls:

And I also loved this graffiti:

There were also claustrophobic concrete hallways:

I wanted to get to the top of both bunkers, but did not manage to get to the roof bar on the Heiligengeistfeld bunker; the Terrace Hill bar was closed even if it was supposed to be open... but otherwise I was able to move inside that bunker, through the shops and offices. The bar would have been nice though, with palm trees on top of cold, grey concrete:

When visiting the Energy Bunker it was hit by a thunderstorm, rain poured down, and I was worried that I would not be able to leave without getting my backpack and computer wet. But the storm was just a front... it passed by:

More pictures from the Heiligengeistfeld tower:


More pictures from the Energy bunker:

At the roof they had an advertisement for small sleeping tents/cabins:

Other pictures from Hamburg:

This tower welcomed us on the way to the bunkers:

Photos (c) 2018 by Jari Arkko. All rights reserved.

Wednesday, August 8, 2018

New skis for the summer!

Skis for the summer acquired, from Ski-service in Pitäjänmäki. They opened the shop for me :-)

The new skis are Völkls, 100mm wide. A bit wider than I had before, and pretty high speed/less turning radius than I had before. Lets see if I like them... at least they run very stably, based on experience so far :-)

Photos (c) 2018 by Jari Arkko.

Sunday, August 5, 2018

Skiing San Marino... on the rocks


San Marino!

It is the 58th country.

Although I can't say there was snow... but rocks on the path from the top of Monte Titano will do. I started from Cesta, the castle at the highest point on Monte Titano at 756 meters, and the rock-floored path down provides a surprisingly good sliding for my plastic "mini skis" by Orthex, the proud sponsor of my blog.

I had never been to San Marino before, and it was an amazing experience also in other ways. The festival to celebrate the victory over fascists was held on the weekend that we visited. There were shows, people dressed in historical clothing, etc. And just the drive up to this tiny nation's mountain peak was a thrill. And the walks on the mountain between the castles were wonderful, night and day. Much recommended.

This blog article is also available on Teton Gravity Research. Tämä blogiartikkeli löytyy myös suomeksi Relaasta. All the Planetskier articles can be found from

Photos and videos (c) 2018 by Jari Arkko. All rights reserved.

Napoli Catacombs

Catacombe di San Gennaro is one of the underground burial sites in Naples. Janne and visited this on a tour, and were surprised.

Years ago, we had visited the Paris catacombs that were indeed a burial site, with many of the bones still remaining in the tunnels. The Naples catacombs surprised us in that they were much more than that.

Yes, there were graves. But there were also several chapels, places of worship, and paintings.  Much more church-like, building-like and not as cave-like as in Paris.

The graves were also individual, selected positions rather than mass collection of bones.

Halls and chapels:

More paintings:


Photos (c) 2018 by Jari Arkko. All rights reserved.

Saturday, August 4, 2018

The Secret Keyhole

What a find! A secret garden, but with a keyhole that reveals the most beautiful view onto it, with St. Peter's Basilica exactly in the centre of the view.

Much recommended. The address is Piazza dei Cavalieri di Malta 3, Rome.

Photos (c) 2018 by Jari Arkko and Janne Arkko. All rights reserved.

Cestius Pyramid

I did not realise there was a pyramid in Rome. Not huge, but still impressive Cestius Pyramid! Modelled after Egyptian or other pyramids, perhaps.

Photos (c) 2018 by Jari Arkko. All rights reserved.

World's Worst Cave Museum

You have to feel sorry for this little museum, as their resources are probably tight. But seriously... cave stalactites made of urethan without painting... bears with zippers... all-white plastic giraffes.

It was particularly striking contrast visiting the cave parts of this museum, as they tried to depict the feeling of Grotta di Frasassi, which we had just visited in person. Lets just say that the urethan did not do the trick for us :-)

The museum also listed other museums of zoology in the world, and got their locations terribly wrong. Stockholm isn't in the south tip of Sweden, for instance, nor is Helsinki at Tampere.

All these wonderful things can be found from Rome's museum of zoology. Much recommended for the entertainment value!

Photos (c) 2018 by Jari Arkko. All rights reserved.

Swim at the Castel Gandolfo

On our last day of the Italian tour, Janne and I drove to Lago Albano, an old volcanic crater that is now filled with water. On the rim of the crater you can find Castel Gandolfo, one of most beautiful Italian towns, the Pope's summer cottage, and wonderful views.

At the bottom of the crater you'll find nice clean water. Although in the August heatwave the water wasn't particularly cool -- 31 Celsius. Nevertheless, a nice plunge into water before flights back home...

We at Ristorante Bucci, with a wonderful view as shown above. They had interesting meat ball dishes, either with cheese Cognag sauce or the red wine sauce... we ordered both:

This restaurant must have one of the best toilet views, too. From the men's toilet there's a window:

Here are pictures from the swim. Note the black sand:

Butterfly on the rim:

More pictures from the restaurant:

Photos (c) 2018 by Jari Arkko. All rights reserved.

Friday, August 3, 2018

Grotta di Frasassi

This week I'm on a tour through Italy with Janne. I had mentioned this to Tero, who suggested that we visit Grotta di Frasassi east of Ancona. He had made a visit earlier, and saw an incredibly large cave hall. Still, I had not realised how big it was. Over 100 meters in free height, and 240 meters to the natural opening at the top.

The size of largest room, Sala Abisso Ancona ("the abyss"), is difficult to imagine, even standing there. A tiny stalactite on the wall turns out to be two and half meters high, but it pales in comparison with the largest ones.

This cave has the most elaborate and untouched stalactite and other cave forms than I have seen anywhere else. It also help that the cave was only discovered in 1971, and has been carefully developed.

The cave has a number of different chambers. One of them is called Sala Finlandia, named according to the land of thousand lakes as that chamber contains may pools of water.

In the 1980s, a psychology experiment was performed in this cave with 15 volunteers. Olli Lehtinen, then a youngster and interested in adventures also participated in the test. There was a recent article in Helsingin Sanomat about the experiment.

Gortta di Frasassi worth your visit if you are anywhere near this place in Italy!

Maps and more information can be found here.

More pictures from the Sala Abisso Ancona:


Sala Finlandia:

A 7-meter stalactite hanging on top of us, close to 100 meters above at Sala Duecento:

Paths elsewhere in the cave:

Here's the entrance to the lower, flooded levels of the cave:

Interestingly, the site for the cave is a tourist gathering, and there are countless vendors selling what is largely just toys and junk; I tried to search for a t-shirt about the cave itself, but did not find anything else than one kids' size one. However, the good thing is that there are multiple vendors selling food and drinks; choice is good.


A rare occurrence: a free ticket for a blogger. Thank you!

Photos (c) 2018 by Jari Arkko. All rights reserved.