(Pic from here via Wikipedia)
Although ThereIFixedIt is usually dedicated to DIY nightmares and the like, it runs a Historical Thursday column which I really enjoy. The latest looks at the monolithic churches of Ethiopia, churches carved out of the bedrock itself. These are truly beautiful and unique buildings that are also a testament to the ingenuity of engineers and workmen, but also to the depths to which religion can motivate rulers and a populace. Some of the churches in Lalibela are about 800 years old, and still going strong.