The image is a compelling one: dozens of bonfires lighting the way to midnight mass at churches throughout Spain. The time is the 16^th century, and the occasion is the final night of Las Posadas, Mary and Joseph’s search for an inn in Bethlehem.

Bonfires made the move to the American Southwest along with Spanish missionaries; here, they might have been made with stacks of fragrant piñon wood. And here the fires were soon replaced, first with lanterns made from colored paper imported from the Orient, later with luminarias or farolitos fashioned from the brown paper bags brought by peddlers down the Santa Fe Trail in the early 1800s.

The bags were ballasted with sand into which a candle was placed, and the warm glow continued to mark Las Posadas or even to announce the occasion of a fiesta. San Antonio, mindful of tradition but ever-ready for a party, embraced both functions from the beginning.

And San Antonio, equally aware of its assets, also takes the tradition to new heights with the Fiesta de las Luminarias. Starting at dusk on the first weekend in December – and continuing each Friday, Saturday and Sunday until December 20^th – thousands of paper bags, each outfitted with the requisite sand and candle, are illuminated on the banks of the River Walk to light the way of pilgrims simply in search of a spectacle: myriad colored lights (122,000, it’s said) drape the cypress trees overhanging the river, and they add their kaleidoscopic reflections to those of the luminarias along the paths below.

If Mary and Joseph do appear during Las Luminarias, it will likely be on a river cruiser in the company of carolers, for caroling by more than 185 school, church, civic and corporate groups is a holiday tradition along the popular waterway. Choral groups will appear from Nov. 28 to Dec. 20 between the hours of 6:30-7:30 p.m. and 8-9 p.m. Four boats at a time will ply the river, stopping at restaurants or wherever a crowd has assembled, and among their ranks will be a bell choir and a group from England that makes the trip each year specifically to serenade San Antonians and their guests.

Walking at one’s own pace is possibly the best way to experience Las Luminarias, but another option gets the reveler right in the middle of things: a barge cruise on one of Rio San Antonio’s vessels. The stereoscopic spectacle will be supplemented by commentary on the historic buildings along the banks, and who’s to stop the wannabee warbler from chiming in with the choirs? Check out the barge schedules at www.riosanantonio.com.

On Dec. 20, the last night of La Fiesta de las Luminarias, it’s possible to recreate the original search for lodging by participating in La Gran Posada. Presented by San Fernando Cathedral, the nation’s oldest cathedral sanctuary, the posada starts at 6 p.m. in  Milam Park just to the west of San Fernando and wends its way through Market Square and past City Hall and the County Courthouse before terminating at the cathedral. Pilgrims hold lighted candles and sing traditional carols and villancicos as they follow Mary and Joseph on their quest.