Still, despite the array of exterior styles, the interiors conform strictly to a layout that reflects the culture’s class and gender differences. Through the front gate, you find a covered area where men conduct business with tradesmen on two raised platforms called thinnai that flank the front door. The door itself is often elaborately carved from a single huge slab of teak, with applied panels that tell stories of Vishnu and Shiva, the Chettiars’ main god. Another set of plinths lie directly inside, where family members might lounge, shaded from the midday sun. Sepia photos of ancestors, especially the patriarch, are arrayed in frames and hung so high up the walls they must be angled down to be admired. Beyond is a tennis-court-size open courtyard; in recent years families have installed metal grating above to ward off gangs of monkeys who wreck the rounded terra-cotta roof tiles in search of scraps of food the birds drop. The courtyard — with walls plastered in a unique silken lime-and-egg mixture — is ringed by a pillared, covered colonnade, often topped with a mezzanine. Off the colonnade there are dozens of cell-like rooms, traditionally stacked to the rafters with thousands of bowls, tureens and urns in steel, brass or colored enamel — dowry offerings handed down through generations. Every marriage adds to the inventory; the status is in the sheer volume.

What strikes you immediately, if you are used to the Western emphasis on upholstered sofas and chairs clustered for maximum conversation comfort and perhaps a cushy snooze, is that there is virtually no furniture. There’s also no privacy. Bedrolls are brought out at night to the interior thinnais, and the family sleeps together (“My children’s best memories are those times,” says Meyyappan, who in recent years has gotten herself a “proper, fixed bed, with a real mattress”); exquisite meals are traditionally served on the floor on banana leaves, and eaten with the delicately pinched-together fingers of the right hand, while in a crouch. “It keeps you limber,” Meyyappan says, conceding, however, that she herself has long given it up for a table and chairs. Despite the elegance of the houses, indoor plumbing came only in the 1940s. Meyyappan recalls coming back to live in her husband’s home after her marriage, as is traditional, and being surprised by a toilet; as a child in her family’s mansion next door, she recalls, “we just went out in the garden.”

The golden era of the Chettiars ended during World War II. The British had for years been angling to cut them out of the financial system of Southeast Asia, and the Japanese booted them from Burma when they invaded. With the economic system in shards, the frenzied building abruptly ceased, and most Chettiars left for Chennai, Mumbai, Singapore and the United States, starting businesses or entering medicine or law. There are now about 120,000 members of the clan in India and beyond.

Image ON THE COVER South India’s Chettinad region is featured in T’s May 21 Travel issue. Credit... Anthony Cotsifas

And yet, even now, Chettiars — the young cosmopolites refer to themselves as “Chettys,” a great conversation starter over a star anise Manhattan at Aer, the bar atop the Four Seasons Mumbai — continue to see themselves as wholly of this place, forever, no matter where they actually live. In 2010, Krishna Chettiar, a silver-haired 90-year-old dressed daily in a meticulously pressed white kurta, was finally convinced to lease his family’s 60-room house to a small Tamil Nadu-based hotel company. They run it now, as Chidambara Vilas, 25 bedrooms luxuriously retrofitted with air conditioning and private baths. One of the few wealthy Chettiars who never left (“Let my daughters come from Chennai and visit,” he says, regally), he negotiated for the hotel company to retain a private annex for him out of part of the mansion’s endless ballroom — a room so long, he says, “that you couldn’t recognize a man standing at the other end.”

Betting that Chettinad has untapped tourist potential, the company would have loved to buy the place outright from him, making him one of the few Chettiars who could cash out permanently. They knew not to bother asking.