If you thought India’s only desert-like landscape existed in the Thar, think again. Hidden deep within Tamil Nadu lies a surreal, fiery-red wilderness that looks straight out of Mars -Theri Kaadu, South India’s stunning red-sand desert stretching across Thoothukudi and Tirunelveli.
A crimson desert born from the ocean
Theri Kaadu’s origins are nothing short of extraordinary. Formed during the Quaternary Period, its sands trace back to a time when sea levels were much lower. As the exposed sea shelf dried out nearly 10,000 years ago, powerful winds carried iron-rich sediments inland. Over millennia, these particles accumulated into rolling red dunes, earning the name ‘Theri’, meaning red ferruginous soil.
This is no typical desert created by heat and drought. It is a geological phenomenon, a fusion of ancient marine deposits and relentless wind action. Scientists call it a “living landscape,” constantly shifting and reshaping.
Why Theri Kaadu looks like Mars
The desert’s dramatic crimson colour comes from its heavy iron oxide content rich in hematite, limonite, magnetite and other iron minerals. According to soil experts, its pigmentation aligns with the 2.5 YR hue in the Munsell colour system, the same shade often observed in Martian soil samples.
No wonder travellers say it feels like standing on the Red Planet.
A desert that never stays still
What makes Theri Kaadu unique is its movement. Unlike most deserts where dunes settle over centuries, these bright red sands shift continuously, sculpted by strong southwest winds. Scientists use advanced dating techniques to track this movement, making Theri Kaadu a natural laboratory for studying climate change, desertification, and Earth’s environmental history.
Life in a harsh red wonderland
Despite its Mars-like terrain, life persists. The desert shelters fan-throated lizards, owlets, kestrels, velvet poochi insects, and hardy shrubs. Palm and cashew trees dot the landscape, though farming remains difficult due to fast infiltration rates in the sandy soil.
A red gem worth preserving
Theri Kaadu isn’t just a tourist surprise, it’s a window into Earth’s past and a reminder of how landscapes evolve. As India’s only red-sand desert, it stands as a geological marvel demanding conservation, curiosity, and awe.