Trips Places Foods Stories Newsletters
Loading...
Loading...
Loading...
Loading...

No search results found for
“”

Make sure words are spelled correctly.

Try searching for a travel destination.

Places near me Random place

Popular Destinations

  • Paris
  • London
  • New York
  • Berlin
  • Rome
  • Los Angeles
Trips Places Foods Stories Newsletters
Sign In Join
Places near me Random place
All Portugal Covão dos Conchos

Covão dos Conchos

This gaping hole in the middle of a remote mountain lake looks like a portal to another dimension.

Portugal

Added By
Henrik Johansson
Email
Been Here
Want to go
Added to list
CAPTION
Covão dos Conchos.   Cro Magnon / Alamy
Covão dos Conchos.   larahcv/public domain
Covão dos Conchos.   im me/cc by-nc 2.0
Lensball photo I   Vrielinkie / Atlas Obscura User
Frogs   Vrielinkie / Atlas Obscura User
Overview of the lake   Vrielinkie / Atlas Obscura User
Creepy crawler   Vrielinkie / Atlas Obscura User
View of the reservoir near the start of the trail   Vrielinkie / Atlas Obscura User
Rocky path to the lake   Vrielinkie / Atlas Obscura User
Portugal 2018   an / Atlas Obscura User
Crag in a rock   Vrielinkie / Atlas Obscura User
  renatss / Atlas Obscura User
Been Here
Want to go
Added to list

About

Despite its appearance, the surreal-looking opening in Portugal's Lagoa da Serra da Estrela is actually not a portal to any other time or place, but rather a manmade funnel leading into a long tunnel. Though it looks like a natural sinkhole lined with cascading waterfalls, Covão dos Conchos is, in fact, a wonder of engineering.

This lake in the Serra da Estrela mountains was artificially created in 1955 during the construction of the nearby hydroelectric dam. Instead of building a pipeline to channel water between Lagoa Serra da Estrela and Lagoa Comprida, the engineers working on the project decided to drill a tunnel through the mountain to connect the two lakes.

The spillway is designed to provide nearby communities with fresh water, but the fact that no other constructions are present nearby makes the funnel seem more like a part of the lake than a part of an infrastructure project. What's more, there are plants growing around the edges of the concrete and granite drain pipe, making the giant hole look even more natural. This sci-fi-looking spillway was a little-known secret in Portugal until photos of the hole went viral in 2016.

Related Tags

Infrastructure Dams Lakes Tunnels Mountains Sinkhole Waterfalls Engineering Subterranean Sites Water

Know Before You Go

Covão dos Conchos is located in the Serra da Estrela natural park and is far from any big city. The hike leading to the spillway starts at Lake Comprida and is around 6 miles (10 km) long. A detailed description of the hike can be found here. Be sure to bring plenty of water and wear good shoes.

Atlas Obscura Adventures

Portugal: A Culinary Adventure from Porto to Lisbon

Explore Portugal through food, from the cities to the seaside.

Book Now

Community Contributors

Added By

hrnick

Edited By

Vrielinkie, an, Meg, renatss

  • Vrielinkie
  • an
  • Meg
  • renatss

Published

January 7, 2019

Edit this listing

Make an Edit
Add Photos
Sources
  • https://flojohntravels.com/2016/06/03/covao-dos-conchos-water-feature/
  • https://www.elitereaders.com/covao-do-conchos-water-hole-spillway-portal-portugal/
  • https://www.wikiloc.com/hiking-trails/rota-das-6-lagoas-serra-da-estrela-13455381#wp-13455382
Covão dos Conchos
Lagoa da Serra da Estrela
Portugal
40.363916, -7.610906

Nearby Places

Covão da Ametade

Loriga, Portugal

miles away

Nossa Senhora da Boa Estrela (Our Lady of the Good Star)

Unhais da Serra, Portugal

miles away

Torre da Estrela

Loriga, Portugal

miles away

Explore the Destination Guide

Photo of Portugal

Portugal

Europe

Places 166
Stories 11

Nearby Places

Covão da Ametade

Loriga, Portugal

miles away

Nossa Senhora da Boa Estrela (Our Lady of the Good Star)

Unhais da Serra, Portugal

miles away

Torre da Estrela

Loriga, Portugal

miles away

Explore the Destination Guide

Photo of Portugal

Portugal

Europe

Places 166
Stories 11

Related Stories and Lists

16 Hidden Gems to Visit in Portugal

List

By Atlas Obscura

Related Places

  • Along the route of the Flåmsbana

    Flåm, Norway

    Flåmsbana (Flåm Railway)

    One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

  • The never-used headgate structure at the west end of the dam.

    Bend, Oregon

    Tumalo Dam

    The ruins of a failed dam that was built over land later described as a "sponge."

  • The Pilchowice dam and hydroelectric power plant (north end)

    Pilchowice, Poland

    Pilchowice Hydroelectic Dam

    The tallest stone dam in Poland was opened by Kaiser Wilhelm II himself.

  • Entrance to the Mount Carmel Tunnel

    Hurricane, Utah

    Zion–Mount Carmel Tunnel

    A tunnel with windows, so you don't miss out on the impressive views.

  •  Seikan Tunnel.

    Japan

    Seikan Tunnel

    The world's longest tunnel with an undersea section.

  • Acequia Madre.

    Santiago de Querétaro, Mexico

    Acequia Madre

    The remains of a centuries-old water system that inspired local legends of secret tunnels.

  • Gea de Albarracín, Spain

    Albarracín-Cella Roman Aqueduct

    This ancient tunnel is one of the most important examples of Roman hydraulic engineering in Spain.

  • Tunnel 33, now collapsed.

    Winter Park, Colorado

    Rifle Sight Notch

    This old train trestle and collapsed tunnel once allowed the railroad to negotiate the steep slopes of the Colorado Rockies.

Aerial image of Vietnam, displaying the picturesque rice terraces, characterized by their layered, verdant fields.
Atlas Obscura Membership

Become an Atlas Obscura Member


Join our community of curious explorers.

Become a Member

Get Our Email Newsletter

Follow Us

Facebook YouTube TikTok Instagram Pinterest RSS Feed

Get the app

Download the App
Download on the Apple App Store Get it on Google Play
  • All Places
  • Latest Places
  • Most Popular
  • Places to Eat
  • Random
  • Nearby
  • Add a Place
  • Stories
  • Food & Drink
  • Itineraries
  • Lists
  • Video
  • Podcast
  • Newsletters
  • All Trips
  • Family Trip
  • Food & Drink
  • History & Culture
  • Wildlife & Nature
  • FAQ
  • Membership
  • Feedback & Ideas
  • Community Guidelines
  • Product Blog
  • Unique Gifts
  • Work With Us
  • About
  • FAQ
  • Advertise With Us
  • Advertising Guidelines
  • Privacy Policy
  • Cookie Policy
  • Terms of Use
Atlas Obscura

© 2025 Atlas Obscura. All Rights Reserved.