It is the holiday season in Europe and of course you could visit the Eiffel tower, the Acropolis or one of many Mediterranean beaches. But if all that sounds dull & boring to you (please say yes) why not do a historical chemistry tour!.

Start of the tour: Leiden (The Netherlands, North Sea coast) at the Boerhaave Museum (a science museum) which commemorates with a special exhibition, the liquefaction of helium exactly 100 years ago by Heike Kamerlingh Onnes. They have all his equipment on display (!) .

Next stop: Teylers Museum (80 km northbound) opened its doors in 1784 as a curiosity cabinet. Among its inventory uranium glass and a 1790 device for reacting hydrogen with oxygen.

Fortress Sonnenborgh (website) in downtown Utrecht (go east, we are still in the Netherlands) houses remnants of a chemical laboratory used by University of Utrecht professor Barchusen between 1702 and 1723.

Leaving the Netherlands behind we move into Germany heading for Bad Münstereifel and the Iversheim lime kiln (in full working order) proudly owned by the guys of the 30th legion of the Roman Army between 150 and 300 AD. And don't say that's not chemistry. Local Dolomite rock (CaMg(CO₃)₂) is heated to 1000°C expulsing carbon dioxide and forming a variety of quicklime (CaMgO). At the construction site water is added to form the hydrate CaMg(OH)₄ and when mixed with sand it can can be processed into any shape. The hardening process is a chemical reaction with (surprisingly) carbon dioxide reforming the dolomite and expulsing water (see a 2008 Chemie in unserer Zeit feature DOI).

Moving even further east Weikersheim Castle holds remnants of an alchemical laboratory built and occupied by Graf Wolfgang II. von Hohenlohe around the year 1600 and an exhibition dedicated to it ( DOI). The poor Graf was almost swindled by master alchemist / con artist Michael Polhaimer with a promise of gold by transmutation of lead. Polhaimer was caught and spent two years in the castle's jail rather than in the laboratory.

Final stop Chemie-Museum Merseburg, near Leuna right in the heart of German chemical industry during both World Wars (ammonia, synthetic rubber, synthetic oil) and one of the biggest chemical plants of the DDR. This chemical science park contains a Haber-Bosch ammonia plant, a plant for the production of syngas and much more ( DOI).

I wonder what they sell in the gift shop.