Quo vadis?

The Old Appian Way (source)

"Where are you going?" Saint Peter, leaving Rome, is said to have asked Christ, whom he is supposed to have met walking towards the city. Christ replied, "I am going to Rome to be crucified again." And where else could such a meeting have taken place than on the Old Appian Way?

The little 'Quo Vadis' Church.

The Church of St Mary in Palmis (Italian: Chiesa di Santa Maria delle Piante, Latin: Sanctae Maria in Palmis), better known as Chiesa del Domine Quo Vadis, is a small church southeast of Rome... It is located on the Appian Way, on the site where, according to legend, St Peter met Jesus while Peter was fleeing persecution in Rome. According to the apocryphal Acts of Peter, Peter asked Jesus, "Lord, where are you going?" (Latin: Domine, quo vadis?). Jesus answered, "I am going to Rome to be crucified again" (Latin: Eo Romam iterum crucifigi).

Inside the little church the Holy Meeting is recorded. Stones of the Appian Way cross the chapel, and a painting of Christ stands facing the city, while one of Peter faces the other way. And in the centre -- a marble block with the imprint of a pair of (rather large-sized) bare feet, said to be those of Christ. Actually, the marble block in the Quo Vadis church is, these days, a replica. The original is in safe-keeping in a chapel in the Basilica of San Sebastian Outside the Walls (a short way down the Appian Way). But all the same - pretty impressive, eh?

Domine, quo vadis?

Eo Romam iterum crucifigi.

As to the history of the little church, there has been a sanctuary on the spot since the ninth century, but the current church is from 1637 (the current façade is 17th century). It's possible that the sanctuary might have been even more ancient, perhaps a Christian adaption of some already existing temple. Of the connection with St Peter, Wiki says:

The presence of the Apostle Peter in this area, where he is supposed to have lived, appears to be confirmed in an epigraph in the Catacombs of Saint Sebastian that reads Domus Petri (English: House of Peter). An epigram by Pope Damasus I (366–384) in honour of Peter and Paul reads: "You that are looking for the names of Peter and Paul, you must know that the saints have lived here."

And the footprints? Well...

The two footprints on a marble slab at the centre of the church...are popularly held to be a miraculous sign left by Jesus. It is to these footprints that the official name of the church alludes: palmis refers to the soles of Jesus' feet. It is likely that these footprints are actually the draft of an ancient Roman "ex voto", a tribute paid to the gods for the good outcome of a journey. 

Leaving footprints...

The little church is popularly supposed to be a sanctuary for travellers, and used to bear an inscription inviting travellers to rest: "Stop your walking, traveller, and enter this sacred temple in which you will find the footprint of our Lord Jesus Christ when He met with St. Peter who escaped from the prison." Apt for a chapel along the Old Appian Way, that famous Roman road.

A traveller inside the Quo Vadis Church.

The Old Appian Way - Via Appia Antica - is generally said to begin today at Porto San Sebastiano in the Aurelian Walls, but when it was built in 312 BC it was an almost-straight 560 km road running from the area of the Circus Maximus all the way to Puglia in Southern Italy. Check this site which advises:

Today the Via Appia starts at the Aurelian wall, at the Porta San Sebastiano. The first part of the road is not exactly pedestrian friendly. It leads along the Quo Vadis church, the catacombs of San Callisto and the catacombs of San Sebastiano to the imposing tomb of Cecilia Metella. From here the road is paved with the authentic Roman stones. You can walk for many kilometres passing the remains of numerous historic tombs.

"The first part of the road is not exactly pedestrian friendly. "
The Old Appian Way today.

Check Wiki for lots of detail, and the information that:

The main part of the Appian Way was started and finished in 312 BC. The road began as a levelled dirt road upon which small stones and mortar were laid. Gravel was laid upon this, which was finally topped with tight fitting, interlocking stones to provide a flat surface. Some of the stones were said to fit so well that you could not slide a knife into the cracks. The road was crowned in the middle (for water runoff) and had ditches on either side of the road which were protected by retaining walls.

Today the first part of the Old Appian Way is a bit of a race track of vehicles and the old stones have been replaced by modern cobbles. But continue on down past the great ruined tomb of Cecilia Metella and you too can walk on the same stones as St Peter and - perhaps - Christ himself. Leave some footprints.

Oh, and we probably shouldn't leave this subject without mentioning the Polish author Henryk Sienkiewicz, who was awarded the 1905 Nobel Prize for Literature, partly in recognition of his novel "Quo Vadis":

The novel Quo Vadis tells of a love that develops between a young Christian woman, Ligia (or Lygia), and Marcus Vinicius, a Roman patrician. It takes place in the city of Rome under the rule of emperor Nero around AD 64. Sienkiewicz studied the Roman Empire extensively prior to writing the novel, with the aim of getting historical details correct. As such, several historical figures appear in the book. As a whole, the novel carries an outspoken pro-Christian message.
Published in instalments in three Polish dailies in 1895, it came out in book form in 1896 and has since been translated into more than 50 languages. This novel contributed to Sienkiewicz's Nobel Prize for literature in 1905. Several movies have been based on Quo Vadis including the 1925 Italian silent film Quo Vadis, the 1951 Hollywood production Quo Vadis and the 2001 adaptation by Jerzy Kawalerowicz. (source)

Bust of Sienkiewicz in the Quo Vadis church.

Via Appia Antica.