Perhaps the most intriguing of all Mangistau’s underground mosques, 10th-century Shakpak-Ata is a cross-shaped affair with three entrances and four chambers, cut into a cliff close to the Caspian coast. The eerily beautiful, Swiss-cheese-like stone that it's cut into was once at the bottom of the sea. It’s 133km north of Aktau and 37km northwest of the village of Taushik – the final 11km, north from the Taushik–Fort Shevchenko road, is down a stony, bumpy track.
Shakpak-Ata's walls are adorned with deeply incised Arabic inscriptions, sculpted columns, weirdly weathered niches and drawings of horses and hands. The cliff is peppered with burial niches, and there’s a necropolis of similar age below it, with more than 2000 tombs.