Another impressive palace is that of Ezana, the first Christian king of Axum. Beneath its floors lies the tomb of Basen, known in the West at Balthazar, the wise man from Africa who came Bethlehem to honor the infant Jesus. Nearby is an equally evocative sight, a simple slab of stone covered in writing. A closer look reveals there are three different languages on it: Sabaean, an ancient Yemeni script; Ge'ez, the traditional language of Ethiopia that still survives in the Christian liturgy; and Greek. This Rosetta Stone of Ethiopia was discovered by two local farmers just a few years ago.

By far the most impressive and famous part of Axum is the main field of stelae. One is that of King Ezana, rising 23 meters into the clear blue sky. On the day we went the crescent moon hovered just above it. An even larger stela lies shattered where it fell nearby. Another stela, measuring 26 meters, was stolen by the Italians when they briefly occupied Ethiopia from 1936-41. Mussolini set it up in Rome as a monument to his power, but within a few years Communist partisans had shot him and hung him up by a meat hook as an object of public scorn. Fascism in Italy was destroyed, but it wasn't until 2005 that the stela finally returned to its rightful place.

These stelae are carved with depictions of windows and doors like houses. Clambering around these monumental remains I wondered about the symbolism. Did it represent palaces built by the kings when they were alive, or a house of the spirit like in Egyptian tombs? Perhaps it had a different meaning now lost to time. There's also the mystery of how these monuments were erected in the first place, and why this incredible civilization declined and was eventually overcome by its enemies. I've been to some of the greatest archaeological ruins in the world and they all have one thing in common--they're all ruins now. We shouldn't assume our own civilization is eternal. If we do, we'll be making the same mistake as the Incas, the Egyptians, the Romans, the Axumites, and dozens of others.

Not far from Axum is the pagan temple of Yeha, dating to about the 8th century BC, although nobody is really sure. The temple, which still stands 12 meters high, is related to the Sabaean culture, which once dominated the southern Saudi peninsula, and it looks like its cousins in Yemen. The place later became a church and monastery, and a cross-shaped window casts a bright yellow light on the interior.

Heading out of Axum, we skirt close to the Eritrean border, still technically a war zone because the two countries haven't signed a peace agreement since the cease fire took effect in 2000. A pair of soldiers, country kids who couldn't be more than eighteen, hitch a ride and tell us how bored they are and how much they miss home. One of them eases an arm around my wife's seat back and gives his friend a proud grin. I look at him to show I've noticed, and he blushes and pulls his arm away. We get to their stop, a bare stretch of road, and they shoulder their Kalashnikovs, waving goodbye and wishing us a pleasant journey.

Next time: climbing to a clifftop monastery and exploring the rock-hewn churches of Lalibela!

You can read the rest of the Ethiopia series here.