The monsoon never arrives quietly in Bangladesh. It arrives like a warning.
The sky darkens without notice, the wind turns damp and heavy, and rivers begin to swell as though remembering an older shape.
In Sylhet, the haors dissolve into endless sheets of water where the horizon disappears.
Far to the south, the Sundarbans, the vast mangrove wilderness straddling Bangladesh and India, become, after nightfall, a world of shifting tides, deep silence, and stories that refuse to die.
It is in this season, villagers say, that the Aleya appears.
Mention the lights to an old fisherman in Satkhira or Bagerhat, and he will rarely laugh it off.
More often, he will fall silent for a moment, eyes drifting somewhere beyond the riverbank, as though remembering something he would rather forget.
In the narrow tidal creeks of the Sundarbans, where water and darkness blur together, the Aleya is known simply as the light one must never follow.
The stories are strikingly similar across generations.
Deep into the night, when the mist settles low over the marshes and the mangroves close in like walls, strange lights begin to appear.
Sometimes it is a single pale orb.
Sometimes two or three are drifting together over the water.
Greenish-blue in color, they hover just above the surface, moving with unsettling intention, retreating when approached, and drawing nearer when ignored.
Fishermen believe they are the souls of those who drowned in these waters, men who left home during monsoon season and never returned.
For centuries, the Aleya has existed somewhere between folklore and fear. In many river communities, the lights are blamed for disappearances at sea.
Some say they lure exhausted fishers away from familiar channels into dangerous currents.
Others believe the lights are warnings, guiding the living away from the fate suffered by the dead.
Either way, few who work these waters are willing to dismiss them entirely.
Science, however, has long attempted to explain the phenomenon.
In the late 18th century, Italian physicist Alessandro Volta linked mysterious marsh lights to gases released from decomposing organic matter.
Modern researchers say the glow is likely caused by phosphine, methane, and diphosphane gases rising from waterlogged soil rich with decaying vegetation, conditions abundant in the Sundarbans.
When these gases react with oxygen in the air, they can ignite or emit a faint luminescence.
Scientists later discovered another curious detail: the lights often appear to move away from those chasing them.
As a person walks through still marsh air, they create small air currents that push the lighter gases forward.
Stop walking, and the light seems to stop.
Turn away, and it appears to follow.
The explanation is rational and measurable and yet, for many, incomplete.
Because science explains the chemistry of the glow, but not the fear surrounding it.
It does not explain why generations of fishermen, separated by decades and geography, describe the same eerie encounter in almost identical terms.
Nor does it explain why similar phantom lights haunt the folklore of distant cultures, from the will-o’-the-wisps of Europe to the ghost fires of Japan and Thailand, each tied to death, wandering spirits, and the dangers of straying too far into darkness.
In parts of the Sundarbans, some fishermen still perform quiet rituals before heading out at night.
A small lamp is lit at the river’s edge.
A prayer is whispered into the wind.
Offerings are placed near the marsh before the boats drift into black water.
To outsiders, it may resemble superstition.
To those who survive by reading tides, storms, and signs invisible to others, it is something else entirely: caution handed down through generations.
The monsoon only deepens the mystery.
Warm water, rotting vegetation, and flooded marshes create perfect conditions for the lights to appear.
It is also the season when fish are plentiful and fishermen venture furthest into dangerous waters.
In Ashar and Sraban, the rivers feed families and sometimes swallow them whole.
At its heart, the legend of Aleya is less about ghosts than grief.
The dead remembered in these stories are rarely kings, saints, or mythical heroes.
They are ordinary fishermen who rowed into storms because hunger left them little choice.
In many cases, their bodies were never recovered.
No grave was built. No farewell was spoken. The river simply kept them.
Aleya, perhaps, became a way for the living to believe the lost had not vanished completely.
Somewhere in the darkness, they still remained flickering faintly above the tide.
Bangla literature has long understood this uneasy relationship between rain, darkness, and memory.
In the ghost stories of Rabindranath Tagore, storms and lonely waterways often become spaces where the living and the dead seem to brush against one another.
Humayun Ahmed carried the same atmosphere into modern Bangladesh, where the supernatural rarely arrives loudly but instead slips quietly into ordinary life.
And perhaps that is why the Aleya endures.
Because in the drowned silence of the Sundarbans, under monsoon skies where mist and darkness erase certainty, the line between science and superstition can feel impossibly thin.
The lights still appear.
Fishermen still speak of them in lowered voices. And when they do, they do not chase the glow.
They stop.
They wait.
And they let the dead pass first.
