If by anything it is characterized by Jaén it is by its olive trees. There are very old people and there are also large ones (which is not about their age) spread over different municipalities in the provincial geography. The uniqueness of the Arroyo del Ojanco olive tree lies, rather than its age, in its gigantic dimensions, so it has been proposed to be declared a Natural Monument of Andalusia. It is said that it is the largest olive tree in the world, and possibly it is, because the figures that cast its measures, referred to in the tab at the beginning of the article, tell us of a single copy. This should be added to its productive capacity, which is around 600 kg. olive per campaign (an adult irrigated olive tree usually does not reach 70 kg).

The two large branches (2.10 and 2.80 m of perimeter) that are bifurcan from its thick fuse bear all the weight of the cup, which becomes of such magnitude - especially when the fruit develops - which forces its dense foliage to rest on the ground at many ends of the cup. Anyway, everything in this portentous specimen is Guinness record.

So long a centenary history has generated some legendary accounts around this olive tree, as it was planted in the Roman era (which indeed built a magnificent villa a few hundred metres from Fuentebuena) or by friars after the Christian reconquest of these lands. Another version states that its size, so different from that of the olive trees around it, is because it was born from a blessed bouquet on a Palm Sunday.

To access the Fuentebuena olive, you have to go from the urban core of Arroyo del Ojanco to the local road JV-7.005 towards Beas de Segura. As you pass the crossing of Prados de Armijo, the olive tree is about 50 metres from the road.

• Your access is made on foot field through.
• The person who best knows and has studied the centenary olive trees in Martos is Mr. Ciriaco Castro Toro, retired technician of the City Council.

We can deduce that this was the dominant landscape a few centuries ago, when after the Reconquista arrived in this village the first inhabitants attracted by the wealth of this dehesa and the possibilities it offered, not only for its cattle, but also to make it "land of bread."

Until the 19th century there were still many oak feet, but it was during this and especially during the first years of the last 20th century that they were significantly reduced, in some cases to devote the land to cereal, vineyard or olive trees and in others to obtaining charcoal. However we can still see some spots of indigenous vegetation in the vicinity of Cabeza Montosa and the hill of the Peones.

This fierce struggle of man against the dehesa has allowed some of the oak to be kept so that its shadow would cover the reapers and the flocks that took advantage of the rashes, or to collect the stones that were taken from the fallow. The fact is that in cases like this, in the face of lack of competition, it is possible that the few specimens of oak have grown more vigorously.

Its trunk has a considerable bearing for an oak and its cup is the widest in the entire province with about 30 meters in diameter and 300 meters in perimeter. This oak is part of the catalogue of unique trees in Spain and is waiting to be declared as Good of Natural Interest, not in vain is of the few millennia trees left on the peninsula.

It is located very close to the railway station of Cabra del Santo Cristo, next to the cortijo of "La Viña." We can access up to the millennial oak through an asphalt road, in good condition, that leaves from the passage to the level that is in the Station. We just have to follow the direction of the signage and within 2 km we will have no doubt when we see it to the left of the road, while to the right the above-mentioned cortijo of the Viña will serve as a reference.

From Cabra we can also walk along the lane that runs through the Fifth, Alamedilla and Gamelloncillo, for which we will walk through space of about 6 km (only one way). It is advisable to finish our route at the station of Cabra and stay in your canteen to take a refreshment with good viandas to recover from the effort, or, if we want to continue to know this ancient dehesa, continue track and return to Hidalgo and the Mill Barranco, but then we will extend our route to about 18 km and have walked by asphalt for a considerable part of the road.

• In some places it is described as a millennial and in others, a centenary.
• Access is made by asphalt road on foot or by car.