I'm not sure by what measure Spain has high land prices. It effectively has the lowest population density of any sizeable (under 11 million) country in Europe [1]. It also has one of the highest rates of second property ownership in Europe [2]. I can't find figures but I suspect it also has one of highest rates of home ownership by non domeciles too.

Lots of factors contribute to all this and like anywhere it's always 'location, location, location', but outside a few major cities and popular holiday locations I think it's probably pretty cheap - in relative terms.

[1] https://en.wikipedia.org/wiki/Area_and_population_of_Europea... [2] https://www.researchgate.net/figure/Secondary-property-owner...

If it's pretty cheap, it won't be allowed to build anything residential.