Atlas Places Categories Resources Discuss

An atlas of Earth’s mysterious places — megaliths, pyramids, lost and sunken cities — with the evidence shown plainly: what is verified, what is contested, and what is still unknown.

Data CC BY-SA 4.0 · Photos per credit

Explore

Atlas map
All places
Categories
Countries
Contested & pseudo

Community

Theories & discussion
Lists
News & resources
Submit a resource

Mysteria

About the atlas
Data & verification
Licenses & credits
Create an account

© 2026 Mysteria. Exploring the ancient world.Map © OpenFreeMap · OpenMapTiles · OpenStreetMap contributors

Search Mysteria

Search places, or jump to a section

Tagssecondary-dam

#secondary dam

1 place carries this tag, across every kind and continent it appears in.

Filters

Verification

Pick several

Verified1 Widely accepted0 Contested0 Hypothetical0 Unverified0 Pseudoarchaeology0

Category

Ancient cities1 Archaeological wonders1 Earthworks1 Hydraulic works1

All categories →

Country

All countries →

Heritage

UNESCO World Heritage only

Excavation

Partially excavated1

1 place

✓Verified

🇾🇪 Yemen · Hydraulic works

Sadd al-Arim Secondary Dam

Sabaean Kingdom 750 BCE - 570 CE · Sabaean (Saba) kingdom

750 BCE Sabaean secondary saddle dam (420 m) and north sluice extension of Marib, doubling irrigated area via 2.1 km north canal.