In the tropical climate of the U.S. Virgin Islands, it’s not particularly strange to walk inside a building and find sand beneath your feet, as you do when passing through the arched entryway of the Hebrew Congregation of St. Thomas, in Charlotte Amalie.

There’s a story behind the sand, as there is for almost every nook of the landmark building nestled into the Caribbean island streetscape known as Synagogue Hill.

When our trio stepped off the cruise ship Norwegian Epic, my sister, brother-in-law and I had one site in mind: The St. Thomas synagogue had been a destination for friends and family members before us, and now we were to make the pilgrimage to the second oldest synagogue in the Western Hemisphere and longest running congregation under the American flag.

Charlotte Amalie, the capital and largest city on the island, harbors steep streets to rival the South Side Slopes, and we had heard the trek was hard on weak knees, so reaching our dock-to-door destination along Krystal Gade (Danish for “street”) was left to a friendly cabdriver. An address was unnecessary. We just said, “The synagogue, please,” and 10 minutes later, we were there, near the top of a residential street and beside a car with a sign in its window that read “Cantor is in the synagogue.”

After taking pictures beside the National Historic Landmark plaque, designated in 1997, we ascended into the rec­tangular, high-ceilinged sanctuary, where the Holy Ark along the eastern wall had been opened to reveal a grouping of six Torahs (scrolls of scripture), much like the ones I’d known from temples in American cities, and one unfamiliar silhouette in the center, a decorated wooden cylinder that turned out to be a Moroccan torah.

A woman wearing a yarmulke and tallis (traditional hat and prayer shawl) told us to check out the museum in the back; she would be with us shortly.

We wandered through the building that had been constructed in 1833 by the Hebrew Congregation of St. Thomas, also known as the Congregation of Blessing, Peace and Loving Deeds. The congregation was founded in 1796 by Sephardic Jews, many of whom arrived on island shores after fleeing the Spanish Inquisition.

Nine Jewish families belonged to the congregation in 1801, but by 1823 that congregation swelled with arrivals from other European countries and island colonies. A citywide fire destroyed the synagogue in 1831, and the building we were standing in was completed two years later. Only once in all the passing years, when Hurricane Marilyn struck St. Thomas, were Sabbath services not held here.

While palm trees waved outside an open window, we began our education about the Jewish settlers who had arrived on St. Thomas starting in the 17th century. The first Reform Confirmation service in the New World was said to have been held here in 1843, and today, the congregation is a member of the Union for Reform Judaism. The impressionist painter Camille Pissarro, born in Charlotte Amalie to a Jewish father of Portuguese descent and native Creole mother in 1830, left half his estate to the synagogue and half to St. Thomas’ Protestant church.

We were also to learn about “the Jewish pirates of the Caribbean” (check out the Random House book of the same name by Edward Kritzler) who aided Gen. George Washington’s Continental Army with materials that found their way through British blockades. Among them were settlers from the Dutch colony of St. Eustatius who sided with Washington’s upstarts because they believed he was fighting for religious freedom.

When the British came after the St. Eustatius colonists, many fled to St. Thomas.

This part of the island’s history was told to us by cantorial soloist Diane Becker Krasnick, a Wisconsin native and the informative guide for our synagogue experience on a Thursday afternoon.

Oh, and the sand. She could go on and on about that.

There are four sand-floor synagogues in the Western Hemisphere. By some accounts, the sand floors relate to 40 years spent wandering the desert in search of the Holy Land. More likely, said Becker Krasnick, the covering commemorates the way Spanish Jews were forced to practice their religion in secret.

She explained that the only way to survive the Inquisition was to convert — or pretend to convert. The cantor said Jews would hide mezuzas (doorpost scrolls) in the feet of statues of the Madonna at the entrance to their homes. They also would practice their religion in cellars and muffle the sound by spreading sand on the floors above, which is the most likely explanation for the indoor sand floors.

There are about 60 current resident members of the congregation, and others — including snowbirds and people who support the historic building — are regular or occasional worshipers.

For us, the visit was both a history lesson and a spiritual experience. The cantor revealed a rescued torah with an inventory number on it, put there by Nazi looters of a defunct Czech synagogue. (The scroll is on loan until another synagogue is built in the Czech Republic. She also read a small portion from the Moroccan torah and, before we left, said a blessing with us.)

Then we said our goodbyes and walked down the hill to the busy business district on Main Street. It was teeming with tourists, but my thoughts were back in the synagogue, a sandy oasis on a humid day on St. Thomas.