Home furniture brand Blu Dot blew up on CTV with help from Roku Ads Manager. Here’s how:

After a test campaign reached 211,000 households and achieved 1,010% ROAS, the brand went all in to promote its annual sales event. It removed age and income constraints to expand reach and shifted budget to custom audiences and retargeting, where intent was strongest.

The results speak for themselves. As Blu Dot increased their investment by 10x, ROAS jumped to 2,308% and more page-view conversions surpassed 50,000.

“For CTV campaigns, Roku has been a top performer,” said Claire Folkestad, Paid Media Strategist, Blu Dot. “Comping to our other platforms, we have seen really strong ROAS… and highly efficient CPMs, lower than any other CTV partner we've worked with.”

Using Roku Ads Manager, the campaign moved from a pilot to a permanent performance engine for the brand.

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In June 1992, a farmer named Wu Anai started pumping water from a pond near his home in Shiyan Beicun, a small village in Zhejiang Province, China.

He had heard the ponds in his area were unusually deep. He wanted to use the land beneath. After 17 days of continuous pumping, the water dropped far enough to reveal what lay below.

It was not a natural basin. It was a vast, hand-carved chamber with soaring ceilings, smooth patterned walls, and stone columns rising from the floor.

He had found the Longyou Caves.

That first pond turned out to be just one of five. Beneath each one sat a massive carved cavern. Systematic exploration of the surrounding area eventually revealed 24 caves in total, all clustered within half a square kilometer at Fenghuang Hill.

None of them had appeared in any historical record. None had been mentioned in local accounts. They had simply been there, submerged, for more than two thousand years.

The five main caverns measure between 18 and 34 meters across. Their ceilings reach up to 20 meters tall, about the height of a six-story building. Each one is supported by three or four stone columns left in place during excavation, tapering at their bases into what researchers describe as fishtail forms.

Across all 24 caves, the total volume of stone removed is estimated at close to one million cubic meters. Researchers who have modeled the construction process calculate it would have required roughly a thousand workers, operating continuously, for about six years.

Every wall, ceiling, and column in every cave is covered in the same precise pattern: parallel chisel marks arranged in bands roughly 60 centimeters wide, each line running at a consistent angle of about 60 degrees.

The margin of error across these markings, measured across 24 separate caves, is less than half a centimeter.

The consistency of this pattern across the entire site suggests a standardized technique applied by a large, coordinated workforce. The technique is not unique in ancient China, but the scale and precision here are unusual.

No comparable carved space from the same region or period has ever been identified.

An excavation this large, carried out in ancient China, should appear somewhere in writing.

Administrative and historical records from the Han Dynasty are among the most detailed surviving archives from the ancient world. Major construction projects of this period, including imperial tombs and early Great Wall sections, are documented. The Longyou Caves are not.

Glazed pottery recovered from the cave floors dates to the Western Han Dynasty, roughly 202 BCE to 8 CE, confirming the caves existed by that period. Some archaeologists place their construction earlier, perhaps during the Spring and Autumn Period (770 to 476 BCE), based on the carving style. There is no scholarly consensus on either the date or the builders' identity.

No tools have been recovered from the site. No inscriptions name the builders. No local settlement has been conclusively linked to the project.

The function of the caverns remains unresolved. There is no religious iconography, no residential infrastructure, and no clear evidence of storage use.

Proposed explanations include fortified granaries, military installations, and large-scale quarrying operations where the extracted stone was used elsewhere. No corresponding construction from the same period and location has been identified.

The arrangement of the 24 caves adds a further difficulty. They are positioned so close together that builders of one cavern must have known the exact location of its neighbors. Yet none of the cave walls share a boundary. Maintaining that spatial awareness underground, without being able to see adjacent chambers, would have required a reliable method of measurement and coordination. What that method was, no one has determined.

Today, five of the 24 caves are open to visitors. The other 19 have received comparatively little systematic study.

Archaeologists, architects, geologists, and engineers have examined the site and produced no definitive account of the caves' origin, construction method, or purpose.

What Wu Anai found beneath that pond in 1992 was not a local curiosity. It was a large-scale, precisely executed underground complex built at some point in China's ancient past by people who left no explanation of what they were doing or why. That the project was completed at all, at that scale and with that precision, is not in question.

Until next time,

Emails From Afar Team

Back in September, the team behind both Letters From Afar and Emails From Afar launched a brand new venture… especially for kids.

Introducing:

Inspired by Pokémon, but with an educational twist, Creature Cards delivers a pack of animal trading cards to your door every month.

In every pack, learn about modern-day and extinct creatures from around the world. Discover their rarity, diets, habitats, size, and even where they fall on a danger meter!

Collect, trade, explore, and learn.