Sunday Mass is not the only kind of Mass. When I’m on holiday in a city I’m so energized that I usually wake up early, a lot earlier than my friends. Sneaking round the streets looking for a morning Mass is far better for the temper than sitting slumped in a chair grumpily reading the same page of the guidebook over and over again; and it’s a far better way of seeing a city from the point of view of the natives.

So this is why I found myself, on the first day of a visit to Rome (my ninth visit, my friend’s twelfth, her friends’ first) awake long before everyone else and wandering south from the Pantheon towards the church of S. Andrea della Valle. I thought it would be rather fun to hear Mass at the church that figures so prominently in the first act of Tosca. (We were planning to see Castel S. Angelo, which figures prominently in the last act of Tosca, the following day).

Like most Baroque churches, S. Andrea della Valle has grand heavy dark wooden doors that seem out of proportion to the entrance of a single person: only a procession could enter them without seeming absurd. But I slipped in, feeling invisible against the massive scale of the façade.

It turned out to be difficult to assess how closely the church resembled opera designers’ representations of it, because it was in the middle of some building works. This early Mass had been moved to a chapel attached to the sacristy: all dark wood and histrionic Baroque paintings.

I have forgotten every detail of that Mass except one. To my left, across the aisle and one row back, was a nun. She was very, very old and her face was one mass of wrinkles. It was one of the most beautiful faces I have ever seen. I could see the glory of her soul burning its way through from the inside. In a year or two she would die and become a being so glorious that (as C.S. Lewis puts it in The Weight of Glory) we would be strongly tempted to worship it – if, that is, the mere contemplation of her did not reduce us to smouldering ashes.

I didn’t have a camera with me. Even if I had, I wouldn’t have known how to ask her permission to photograph her – not without sounding like the crassest kind of tourist.

On the way back the air was still fresh and invigorating, and as I joined my friends for breakfast I was determined to go to early Mass every day for the rest of the trip. But in the end I didn’t, not even once.

Rather than editorialise, I thought that this time I'd just give you an extract from a travel journal from 1995:

Sunday 30 July

“We're sitting, Freddie and I, in the bar of the Pera Palace Hotel. We're the only people there. He is reading a book on Sufism and I've been looking through the guide-book and thinking that everything looks too much effort. Fortunately F. thinks so too: we had a very tiring day yesterday. Presently we'll wander out and get some lunch, and then we'll see. Paul (our art historian friend) was a bit fractious this morning and has gone off to the Archaeological Museum to refresh himself or do some work on an early fresco of St Francis or just get away from us. I actually feel a bit get-away-from-ish too, because I'm really quite tired.

“This morning's Mass was at St Antuan on Istiklal Caddesi (the main fashionable shopping street of Istanbul). We'd really come to find the Chaldean rite – ancient, parts of it in Aramaic, mostly attended by prehistoric people from south-eastern Anatolia – but we'd been given the wrong time when I rang, and the Mass was in English, with a lot of Filipinos and some Africans (perhaps Sudanese). I found it simple and quite moving, even things I'd normally hate such as the guitars and "Amazing Grace" during the offertory and some hymns in Tagalog after the consecration and after Communion. For the Creed and the hymns they had an overhead projector showing the words (which is how I know about the Tagalog) and a little bouncing ball moving from one word to the next to keep you in step.

“Paul, who is Russian Orthodox, found the whole thing rather shoddy and undignified, but I always feel put to shame when simple people praise God so un-self-consciously (there was also a rather splendid peasant woman near me, full of age and upright dignity, and rather a pretty choir).”

It was September 21 and my last day in Oaxaca: indeed, the last day of my 2-week trip to Mexico.

I woke up early and went wandering through the town. Not the least attraction of Oaxaca is that its climate is always equable – permanent shirt-or-light-jacket weather. The sun hadn't risen yet but the sky was light. Remembering that this was the day of the autumn equinox and that sunrise would be at 6am (or 7am summer time) throughout the world, I positioned myself in a picturesque spot by Nuestra Señora de la Soledad and waited.

And waited.

It was evident that the Mexican sun was a leisurely orb, and what had started as a spontaneous good idea was turning into something sterile and laboured. So I walked up the hill to the church of S. Domingo. Without giving myself time to think I went in to early Mass.

It was pretty well attended – perhaps 40 people, far more than the proverbial "three charwomen and a cat" of English church services, and a more mixed congregation than the evening Mass, which tends to be packed with rosary-saying female stormtroopers. There was an interesting thing when the time came for the bidding prayers. After the first few prayers, odd members of the congregation started to stand up and call out something to be prayed for. Each petition would be heard with respect and after the pause there would be the usual "Lord, hear us / Lord, graciously hear us".

That sort of thing is beautiful and incredibly difficult to organise. It demands trust, for a start. We have to trust that those who stand up will not use their moment of fame to make political or controversial points, because that is a despicable invasion of our moment of vulnerability and openness to God. We have to trust that those who stand up will be competent and have some idea of what works as a bidding prayer and what doesn't – which all adds up to the fact that you need a congregation that has experience of working together, not merely a collection of random arrivals. And of course we have to trust the priest as well, to trust us to do it and to know when to bring the bidding prayers to an end – neither too soon nor too late.

He did just that, while I was still dealing with my stage fright and deciding whether pilgrims in Spanish were "pelegrinos" or "peregrinos" (no-one would have minded either way, but it was a good excuse for delaying).

On the way out, the Stations of the Cross had started, so I stayed, not really wanting to but not able to persuade myself not to. They were taking it in turns to do each station, using a book that they all had (Guía del Peregrino, so it's just as well I didn't say "pelegrino"), and after one or two stations I was really gripped, because of the thing itself and because the G. del P. has rather splendid commentaries and prayers for each station. It was extra moving to see a crowd of rather poor people (I could imagine them to be porters and street-sweepers) doing all this for themselves without the instigation of the priest.

I got nearer the centre of the group and by the 11th station my neighbour offered me his book and suggested that I do the 12th. I hesitated because I didn't know how to say "12th" (décima secunda)… got over that, got ready to do the 13th, but was pipped at the post because some woman at the back started saying it. I then realised that there was no set order and it's just whoever jumps in first… I was rather upset because I felt it would have been a great honour to do it, but there we are, next time perhaps. At least having the book meant that I could say the Our Father at last instead of miming it.

Afterwards I explained to my neighbour what had happened. His name was Victor and he was very friendly (we used "tú" at once). We expressed a lot of good feeling, I explained I was leaving the city, he asked when I'd be back, and we ended with "Dios te bendiga" on both sides. Outside it was light, and he went off to his work and I back to the hotel to have breakfast with my late-sleeping friend.

One of the earliest things I remember learning from my friends about the law of the Church was the useful fact that travellers were exempt from the obligation of attending Mass on Sunday. (This is just the sort of thing that shocks pious Protestants and gives rule-dodging Catholics a bad name).

Leaving the question of obligations aside, and not going too deeply into whether a tourist is a “traveller” anyway, I’d like to recommend Mass tourism as an excellent exercise, both deepening one’s piety and bringing one closer to the people where one is staying. We are forever complaining about guidebook-clutching tourists lifting their noses from their books just long enough to verify that yes, they have visited this or that Sight, before rushing on to the next Sight on the list: we complain even when we do it ourselves. We complain about the theme-parkification of the places we visit, of history and culture packaged up into easy-to-digest undemanding chunks. We complain, above all, of how we exist in a vacuum, invisible, uninteracted-with, isolated from the locals and unable to meet them.

And all the time the churches are sitting there, waiting to fulfil our needs, and we pay no attention to them except as monuments.

I’m not holding myself up as an example of piety. There are times when I’ll find any excuse not to go to Mass (“God will understand”) and I am a master of being late for Mass without having intended to. But – the times I have been to Mass while on holiday have yielded an amazing number of uplifting, moving and simply enjoyable moments, and in future postings I’ll tell the story of some of those moments as an encouragement to you to take up Mass tourism as an activity.