14th century mural portrait of Tsar Ivan Alexander from the Rock-hewn Churches of Ivanovo

The Rock-hewn Churches of Ivanovo (Bulgarian: Ивановски скални църкви, Ivanovski skalni tsarkvi) are a group of monolithic churches, chapels and monasteries hewn out of solid rock and completely different from other monastery complexes in Bulgaria, located near the village of Ivanovo, 20 km south of Rousse, on the high rocky banks of the Rusenski Lom, 32 m above the river. The complex is noted for its beautiful and well-preserved medieval frescoes.

• http://en.wikipedia.org/wiki/Rock-hewn Churches of Ivanovo
• Hillman 1000 Wonders