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European IMC No.1 S - P - Tide Mills [Almada] Multi-cache

This cache has been archived.

MAntunes: As the IMC Nº 1 primary cache is no longer available, this one has no justification to continue.

So, the spot is available for another cache that brings more persons tho the place that this one did.

Thank you all who visited this cache, and participated in the first International Multi Cache, and thanks to everyone who helped me with this cache by giving me informations related to the access to the place.

The container was removed today. so, no geolitter was left in the place.


Hidden : 06/01/2003
3.5 out of 5
1.5 out of 5

Size: Size:   regular (regular)

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Geocache Description:

"This "secondary cache" can only be found with international team-working because:

This cache is just one cache of a set of 30 caches named European IMC No. 1 … (IMC = International Multi-Cache). These caches are hidden in 15 European countries:

Austria (A), Belgium (B), Denmark (DK), Finland (FIN), France (F), Germany (D), Great Britain (GB), Hungary (H), Ireland (IRL), Italy (I), Luxembourg (L), Netherlands (NL), Portugal (P), Spain (E) and Sweden (S).

In each country there is a "primary cache" and a "secondary cache".

The 15 primary caches are named "European IMC No.1 P-x - yyy" and the 15 secondary caches "European IMC No.1 S-x - zzz" where x is the country code given above and yyy and zzz can be any additional name.

The primary caches are almost like traditional caches. The only difference is, that they contain beside the "normal" content (stash-note, logbook, pencil, give-aways) a "lists of hints" for the secondary caches.

To be able to search and find a secondary cache you need all hints from all 15 primary caches!

As the primary caches are scattered all over Europe it will either require a lot of travelling or - and that is the intention of the European IMC No. 1 - international cooperation:

If you want to find this secondary cache, you should:

1. Find a primary European IMC No. 1 cache (Castelo de Bode area).

2. Contact finders of other primary European IMC No. 1 caches and exchange the hints.

3. Puzzle the hints together and …

4. … email me the hints to get from me the the final coordinates of this one (see note below in the waypoints area) and...go and seek the secondary cache.

The European IMC No. 1 team wish you good luck!"


In the ages where the sources of power became scarce and were limited only to the muscular force, to the wind and chains, the tide mills had a great advantage over other forms of energy: its constancy and previsibility. Two daily tides exists what guarantees about 4 hours of milling. They were constructed in the estuaries of the rivers in low lands, and sheltered zones that allowed to dam waters.

The first tide mill that it has knowledge appears in c. XII in the south of France. During c. XIII and XIV they had become enlarged for all the Europe. In Portugal the first reference of tide mills mentions it in "Castro Marim" in 1290. In 1313 it has notice of one in "Alcântara (Lisboa)" and 1386 in "Montijo". In 1403, Nuno Álvares Pereira, that was owner of almost all the lands bathed by the arm of "Tejo" river that enters in the "Seixal" area, ordered the construction of the mill of "Corroios", the first one that was risen in that area. In 1404 the goods that had in the zone of "Seixal", including the tide mill, had been donated to the Convent of "Carmo". From c. XV the "Carmelitas" promoted the construction of other mills in that area: the mills of "Raposa", "Galvão", "Capitão", "Passagem" and "Torre". Other mills raised in the left edge of the "Coina" river, in this century too. With the earthquake of 1755 almost all mills had been in ruins having been in its bigger part restored or exactly rebuilt.

In almost all the estuaries of the Portuguese rivers mills has built, but the region of "Seixal", consisting of low land and flooded by the estuaries of "Tejo", facilitated its construction. In c. XVI, between "Almada" and "Montijo", has been observed about 60 devices! Next to the mills ports existed where the boats used in the transport of flours and the transport of the region's products began.

Already in this century some mills had other uses. They prepared fish flour, seasonings and peeled rice. Many of them had arrived until our days, but the "Corroios" tide mill kept to work until the 70s. This mill, apt to function, was acquired by the City council of "Seixal" in 1979 that kept it safeguarded and open to the public as an industrial monument.

In the Natural Park of "Ria Formosa", near "Olhão", it conserves an exemplar of the existing mills in our country, also opened to visits and in perfect condition of functioning. It functioned since its construction, in 1885, up to 1970. The mill of "Marim", equipped with six millstones, was recouped in the decade of eighty for the National Service of Parks.

Still in the "Algarve", they still exist about of twenty mills in the river "Arade" between "Portimão" and "Silves", almost all in bad state or reduced to ruins, but they certify the importance that they had long time ago for the local economy. In the Municipal Park of "Sítio das Fontes" close to "Estombar" about three kms from the estuary of river "Arade", there is the only unit, with the miller's home, to work in full producing the flour with wich the local bread is cooked. The recovery of this tide mill and all the environment around is due to the City council of Lagoa efforts.


During the flood, the casters are stopped and the floodgate of the boiler opens automatically with the force of the water that enters.
When the tide starts to leak, the floodgate closes with the contrary force of the water. The water in the boiler is remained dammed until the difference of the height of the tide during the ebb tide puts the casters short. The doors of the pipes to the casters confide then that, on to the millstones, start to grind until the beginning of the flood.

To notice that the hours of the tides compelled the one that it at any time of the day or the night therefore the mills alone worked during the ebb tide. The other hours were used to advantage for cleanness and maintenance of the whole set. For a better exploitation of the system, some boilers of the mills were used to advantage as fisheries of fish and oysters.

The Hunt:

To hunt this cache, You'll have visit to the IMC Nº1 primary cache in Portugal (Castelo de Bode), take a hints sheet, exchange the hints you found with finders of the other European IMC Nº1 caches and email me the final set of hints for Portugal, and I'll send you the coordinates of this cache (see note below in the waypoints area).

Cache Content:

A container with the usual stuff and some documentation about the tide mills.

Don't forget: "Cache in, trash out" and Leave No Trace

This cache is of interest of all European Geocachers. Please, log in English too.

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Additional Hints (Decrypt)

Vg'f qrrc vafvqr gur ohfurf, ng 15 pragvzrgerf sebz gur sybbe - cyrnfr xrrc vg nobir gur sybbe orpnhfr bs gur gvqrf.

Decryption Key


(letter above equals below, and vice versa)