Some travelers take mission trips. Some take journeys of faith. Some take architecture tours of world churches.

But sometimes, regular people on vacation just happen to decide to attend a religious service — sometimes not even of their own faith — and it sticks with them forever.

“I think that when you travel, the very act of being taken out of your own environment opens you to new experiences. Somebody said, ‘We go through life sightless among miracles.’ And in part, that is because in the routine of our lives we stop seeing what is going on around us,” says Stuart Matlins, editor of “How to Be a Perfect Stranger” (Sky Light Paths, Fifth Edition, $19.99) a guide to navigating religious services of all types. “When you are in a foreign or different environment, suddenly all your senses are heightened. You see the unusualness of life. It’s not unlike witnessing miracles.”

Matlins is Jewish, but he has attended multiple services around the world, from cathedrals in Frankfurt and Barcelona to a mosque in Pakistan and a synagogue in Krakow.

“Sit in the back is really the best advice for anyone going to any religious service with which they are unfamiliar,” he says. “In every circumstance, sit in the back, and you can’t go wrong.”

It takes a leap of faith to attend a religious service that is not your own. Even services of one’s own faith can have twists.

But often, the experience is so vivid that it sticks with travelers.

For Richard Shook of Bay City, Mich., the mass he went to in Xi’an, China — in Chinese — was as impressive as seeing Xi’an’s famous terra cotta warriors.

The doors remained open during the February service “so everyone remained in their heavy coats — even the priests wore them under their vestments,” says Shook, 70. “The church seated maybe 250 people and was full a half-hour before mass started — and as people continued to arrive, they brought out little blue plastic stools to fill every available space.”

Why are these small details etched so clearly in travelers’ memories? David Crumm, editor of ReadtheSpirit.com, believes that attending religious services while on trips lets travelers connect with others at a more visceral level beneath the tourist veneer.

“People travel widely — then never actually engage with people,” he says. “One way to authentically engage is to go to churches or religious services. I’ve done it throughout my life.”