The photos provide intriguing glimpses of life among the revolutionaries
An unpublished archive of photographs of Fidel Castro and his fellow revolutionaries paints a fascinating picture of their life in caves and mountain hideouts in the 1950s.
The Fundacion de la Naturaleza y el Hombre emerges out of the vegetation in Havana's lush embassy quarter.
The scene is appropriately green, as this modest building is the headquarters for one of Cuba's leading environmental movements.
The cave was dripping with stalactites, and with dramatic lighting it looked like the set for a James Bond film.
Not that I arrived in the greenest of ways. I had crowded into one of Havana's much loved, but often clapped-out, 1950s taxis, watching the road passing by through a hole in the cab's floor.
The Fundacion is listed in tourist guides as a working museum. It is not on the must-see list for visitors on the beaches, bars, and Buena Vista beat.
People making their way to this out-of-the-way attraction are lured by the books and memorabilia of Cuban anthropologist and revolutionary Antonio Nunez Jimenez - or simply Nunez, as he is known.
Pictures show Mr Castro (centre-right) and "Nunez" (centre-left) meeting farmers
In his former home, I saw the canoe used in his Amazonian expedition of over 17,000km (10,600 miles) from river's source to the sea. He completed it not long before he died in 1998 - a national hero.
There were cases of medals, geological specimens, artefacts from the Amazon, head-dresses and a large collection of erotic Meso-American figurines once described as the "Latin American Kama Sutra".
I shifted my eyes to his 30 books. One was about cigars, but other works were rather more inflammatory, despite their modest topics - Cuban geography and agriculture.
Before the revolution, copies were destroyed for exposing the agrarian class system. But Nunez's research was invaluable to Fidel Castro and Che Guevara, and they became comrades and close friends.
Mr Castro and Nunez feature together in photos which I followed along the walls and up the dim stairs to the offices.
But what was this?
Castro and his men appear to have survived on crabs and raw horse meat
Mr Castro appeared to have set up his headquarters in a vast cave. It was dripping with stalactites, and with dramatic lighting it looked like the set for a James Bond film.
As I peered closer, an English-speaking student called Helema explained this photo had been taken in the Gran Caverna de Santo Tomas, a huge cave system on the west coast at Vinales.
Framed by this atmospheric setting, Mr Castro and Nunez were captured discussing Cuba's plans for what we might now call eco-tourism.
Mr Castro was drawing up his new agricultural policy at the time. He wanted to know how Cuba's farmers could be involved with the tourist economy, without being exploited by it.
Helema said there were other photographs - if I was interested. She indicated a library wall lined with albums, each containing several hundred uncatalogued black and white prints.
After getting permission, I sat down at a long wooden table and began to look through them.
Some were stamped with the official mark of Mr Castro's presidential palace, or his press office.
Others had the signature of Raul Corrales, one of Cuba's "epic revolutionary photographers".
These were classic shots of the period:
- Mr Castro with his followers in their Sierra Maestra hideout, where he directed the revolution from 1956 to 1958, apparently on a diet of crushed crabs and raw horse meat
- Mr Castro with his distinctive pedestal microphone silhouetted against the sky
- Mr Castro and Nunez, the agrarian intellectual, speaking at the centre of a cluster of farmers
- Mr Castro with Nunez, the adventurer, posing with a huge alligator, or even the famous Cuban crocodile
For Nunez's daughter, the photos are family history, given that many of the photographers were friends. She told me later she was trying to get her father's early written works republished and translated, and hoping there would also be a photo biography.
Giddy after hours absorbing the photographs, I was inspired to change my Cuban plans.
The next day I headed south-east to the Sierra Maestra. I found a modest hotel in the foothills, and was given, I was told, the room "slept in by Castro".
I found the compulsory guide, and next morning we began climbing through rocky undergrowth, so dense it sheared off the soles of my walking boots.
Finally, we reached the revolutionary stronghold. A cluster of huts, with amazing views. From here, Mr Castro had broadcast on his Radio Rebelde.
It is still a restricted zone, and photography is banned. But I can report that the broadcast equipment was remarkably well preserved after 50 years.
My guide led me to a large hole in the ground, where, in true James Bond fashion, the radio antenna would rise up under cover of darkness.
The next day I travelled north to the finca - or farm - where Mr Castro grew up. I was the only visitor, so had the full tour, including the dozens of family photographs.
No doubt some will feature in Mr Castro's memoirs, but I wonder if they will also include the Boy's Own adventure yarn behind Antonio Nunez Jimenez, and that crocodile?
Castro used a system of caves as a hide-out, equipped with lighting
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