Alcazaba and Arab baths
In the 10th century Almería was a thriving port city under the Caliph of Cordoba, Abd ar-Rahman III. They developed the relevant infrastructure to go with this and you can visit - the old Arab cisterns have anachronistically been opened as a museum of traditional Spanish culture. If you want to experience Arab baths a hotel on the old market square has opened an arab-bath experience on the site of a historic bath. At 25E for 2 hours it is good value - you get to use all the facilities, including the flotation tank which was a personal favourite of mine and you can drink as much mint tea as you like!
The Alcazaba or castle also arrived in the 10th century, the distinctive ramparts still dominate the city's skyline although you will have to walk slightly beyond the modern city centre and climb a hill to get there. If you can climb all the steps before it closes the castle and its gardens are free to enter and offer great views of the surrounding city and coastline - aspects that were no doubt fundamental to its original creation.
It would be easy to confuse this 16th century building with a castle, as it is so well fortified, but it is in fact a cathedral. You do have to pay to get in but it wasn't expensive, maybe 5E, and an audio-tour in English was included in the ticket price. It was quite ornate and pretty inside, a nice place to spend an hour or two but its not a 'day-visit' location.
Refugios de Almería
If you like your history a little more contemporary you can take a subterranean trip through the underground bunkers used by the residents of Almería during the Civil war. This was a really great way to spend an 1hr and a half or so and was not expensive. 3E for a video subtitled in English and then a guided tour in Spanish - with brief summaries given in English too - is really good value. Although it is essentially a series of concrete tunnels they have done a good job of bringing people's stories to life and I particularly enjoyed the underground hospital reconstruction.
(Hospital in the bunker)
The Museum of Almería
This is hands-down the best free museum I have ever been too; that is quite a claim as I have been to many museums, but its true. The museum covers the region's history spanning from Los Millares to the present day with a focus on the early history of the region. What was particularly striking about this museum was the way they fused audio visual with artistic installations by local artists and genuine artefacts, the integrity of presenting real objects wasn't compromised by experience but enhanced by it. I was particularly impressed with a map of the Los Millares site - you could see the geographical layout of the site but you could also learn about their attitude towards the economy and spirituality, for example, through symbolic objects such as beads, shells.
(Los Millares map with symbols)
With Morocco visible across the water, Almería as a town and as a wider region exists in this liminal space - with a foot in each camp of Europe and Africa - but definitely no-one's pet! Almería owns its ancient heritage; continuing ancient practical practices like building houses into the rocks and cave structures; since the Chalcolithic they have been artisans, creating copper from raw ingredients, firing pots in ingenious fashion whilst looking after the landscape around them.
Luckily for me Almería has been off the tourist track for a long time - as successive governments have ignored it and refused to invest in the area - this has caused real problems financially for the area and is part of the reason why we have the unsightly 'plastics' today, but is also the reason for incredible scenery and for that I am grateful.