CAMBRIDGE, Mass. -- When you walk along Memorial Drive, the monastery of the Society of Saint John the Evangelist appears insular, closed off behind tall fences. But open a small side gate and the place surprises at every turn and every entryway.Perched on prime Charles River real estate, on the edge of Harvard Square, the monastery offers unexpected sanctuary. Thick, stone walls muffle traffic noise and create an architecturally inspiring place. The blend of Italianate and Romanesque design, the arches everywhere, evoke an older time and place. And most unexpected, the monastery is vibrant and engaged with the world outside.The Society of Saint John the Evangelist (SSJE) welcomes guests with what one frequent visitor called "radical hospitality." For the Episcopalian monks who live at the monastery, that means listening attentively, providing spiritual direction, and sharing prayer and meals with visitors. For overnight guests, that often translates into a retreat where days follow a slower rhythm, where visitors find a calm environment for reflection on life and religion."It's really a place for me to recharge," said Lucas Fleming, 50, a criminal defense lawyer from St. Petersburg, Fla., who visits at least once a year. "I can download all the stress that I'm under and I come out feeling a lot better, a lot more relaxed. I liken visiting the monastery to doubling your vacation time. If you go for three days, it feels like you've been gone a week. When I'm there, I feel myself functioning at a much slower pace, a much more intentional pace, a much more meaningful pace."Stepping into the guesthouse, something about the simple decor -- the dark trim against white walls, the Oriental rugs, the original hardwood floors -- is warm and welcoming. It feels like someone's home, albeit a very quiet home. Not far from the main entrance, the first-floor common room features a fireplace flanked by two windows with river views. A sign on a coffee table reads: "We ask that you please respect the silence for which many guests come on retreat."The same request appears throughout the guesthouse and sets the relaxed, contemplative tone. To use cellphones, guests step "off campus," outside the monastery's fences.The guesthouse has 13 single rooms for overnight visitors, including a handicapped-accessible room on the first floor. Named after saints and apostles, the rooms are small and minimalist. Accommodations include a bed, bureau, chair, desk, closet, sink and window overlooking the river in a narrow, roughly 60-square-foot space. Decorations include crosses and icons. Both the second and third floors have four bathrooms for guests to use. On the lower level there is a dining room, a kitchen for making coffee and snacks, and a small chapel used mainly for meditation.The monastery suggests donations ranging from $100 per night for individual, self-guided retreats ($50 for students) to $125 per night for "companioned" or group retreats ($65 for students). During a companioned or group retreat, a brother at the monastery is available for spiritual guidance and one-on-one meetings. Generally, visitors stay two to four nights.Each year, approximately 1,000 guests stay at the monastery in Cambridge, while another 500 go on retreats at Emery House in West Newbury. Emery House is the SSJE retreat center that offers lodging in hermitages and rustic cabins, in addition to rooms in a main house. To accommodate guests on retreat and maintain the brothers' ministry, the monastery and Emery House, SSJE relies on charitable donations from individuals. Guest donations cover roughly 10 percent of the SSJE's annual budget.Guests come from all around the world and all walks of life: men and women, students and lawyers, teachers and bankers, social workers and real estate agents. They are not all Episcopalian, nor all Christian. While some visitors are ordained, most are not members of any clergy. Still, as Brother Jonathan Maury said, "The one thing that kind of unites everyone is that they're seeking God in some way or other." That may mean attending daily religious services at the monastery, sitting in silence in the guesthouse common room, walking through Harvard Square or heading to Fenway Park. Visitors are free to follow their own schedule and go wherever they want outside the monastery, though many structure their stay around daily services and meals with the brothers.From December 2011 to July 2012, Amy Jones, 26, a graduate student at the University of Wisconsin, visited the monastery every month. She described the retreats as ideal for "people who are searching, and that could be for most anything.""A retreat allows a space where your attention is not demanded by other things," said Jones. "You're able to focus. When you're given the space and permission to take the time you need, really interesting thoughts come to you. I would say it's for anybody who needs to step back."As organ music fills the main chapel and worshippers enter a grand space with stone arches, marble floors, intricate stained-glass windows and iron gates, it is easy to step back and reflect. The monastery holds four prayer services throughout the day where guests can join the brothers. "The major purpose of the retreats is to invite people to come and pray in our rhythm," said Maury. For many visitors, the most memorable moments come during services when the brothers join in traditional chants, their voices perfectly complementing one another's in a way that is mesmerizing.After evening prayers, overnight guests eat dinner with the monks in the monastery refectory. Since the monks rise early and go to bed early, dinner is light -- typically soup, salad and homemade whole-wheat bread -- and often vegetarian. Simple, healthful eating is part of the monastic lifestyle in which visitors take part. There are two "talking" meals each week, while the rest are either silent or feature music or a book read aloud. The "talking" meals provide a casual setting for wide-ranging discussions between the brothers and their guests."People are often surprised by the accessibility of the brothers and their lives," said Maury. "We're not aloof or so otherworldly that we're unapproachable. People are often surprised, too, by their ability to be present with us, to take part in the experience of silence and the rhythm of prayer and intentional living that we have. You discover there's something innate about that approach to living and being. It's been there all along and somehow never had a chance to grow."While the monastery's location is curious for a religious community that values quiet contemplation, it was intentionally built near a world-famous university. The Society recognizes that college students are at a "critical stage of life formation" and believes it can provide guidance. The first SSJE monastery was built near Oxford University in England.The Cambridge monastery sits on land purchased with donations from early benefactor and worshipper Isabella Stewart Gardner. Nearly a century ago when the Society settled by the Charles, the location was a surprisingly undesirable, industrial spot abutting an MBTA elevated car depot and Harvard University Press buildings. Construction on the main monastery buildings started during the Great Depression. Recently, the SSJE underwent a $13 million renovation, in part to better accommodate guests. After all, the monastery wants to be as welcoming as possible."The monastery is about the quality of relationships -- your relationship to God and to other people," said Jamie Coats, director of the Friends of SSJE. "We think about the services. We think about the food. We think about how the place is built. We think about the economics. All so you can have a place where you feel safe and truly think about the things that matter to you."