Some call it the extraterrestrial river, the Martian flow of Spain, the most acidic river in the world, and many other names that try to approach and understand the reality that can be appreciated after visiting the river.

If there is one thing we agree on, it is that it is out of this world. In this article, I will tell you everything you need to know about the Red River (or Rio Tinto) in Spain, its origin and explanation of its waters, where it is located, and the best activities to visit.

After this post, you will realize how strange and particular the biodiversity and ecosystems in Spain are, one more reason not to miss this paradise in the Iberian Peninsula.

All “normal” rivers have blue waters or the color they reflect, right? Well, you will be surprised to know that this particular river is controversial for being the only river in Spain with red waters. Throughout the article, you will understand why NASA considers it a protected space for research since it is similar to the conditions of life on mars…

We will stop on this later. For now, let’s start solving doubts…

1. Where is Rio Tinto located?

The Red River, known as Rio Tinto, is located in the coasts of Southern Spain. It runs along the province of Huelva in Andalucia. The river rises in the Sierra de Padre Caro and reaches the Huelva estuary, merging with the Odiel river.

And, from the north, where its source is located, to the south, where it flows into the river, the river crosses the following Huelva municipalities: Nerva, Minas de Río Tinto, El Campillo, Zalamea la Real, Berrocal, Valverde del Camino, Paterna del Campo, Niebla, La Palma del Condado, Villarrasa, Bonares, Trigueros, Lucena del Puerto, San Juan del Puerto, Moguer, Palos de la Frontera and Huelva.

2. Why is the red river red?

The particular Red River is red due to the dissolution of minerals, oxides, and irons.

A long time ago, it was discovered that the Rio Tinto contained iron, copper, zinc, and arsenic with very high acidity and a pH of less than 2. All of this together makes its waters gain a red color. However, other reasons are being analyzed by science. In addition to being red, the waters of the Tinto are dense, with a significant lack of oxygen. This means the “normal” type of life (fishes, vegetation, or amphibians) does not exist. Ironically, some scientists say that this extreme environment of red color is also due to these photosynthetic organisms.

But what does that mean? The Astrobiology Center (CAB) researchers have discovered a life cycle in which bacteria take advantage of the minerals and transform them. In simpler words, a bunch of hungry microorganisms eat the metal sulfates and, so to speak, poop iron oxide. In short, the microorganisms inside it are the ones that change the ore, and the river’s color.

3. History of the Red River

Now let’s travel in time to know the curious origin of this river. A long time ago, in the early 3000 BC, the Iberians were already extracting copper on the shores of the Rio Tinto. The Phoenicians followed in their footsteps, and the Romans and the Muslims came after them.

The mining search extended throughout its history, and they discovered that apart from copper, its shores were also rich in iron and manganese. It was in the 19th century that mining began on a large scale, carried out by English companies.

The exploitation of its shores continued until it reached its maximum activity in 1930. Later, around 1986 and 1996, silver and gold were also seen on its shores. Years after, in 2010, there was an attempt to reopen mining in the area, but this attempt was thwarted mainly for environmental reasons.

4. How long and deep is the red river in Spain?

The Red River, or “Rio Tinto” in Spanish, has a length of 100 km and a basin area of 739 km². It runs along the province of Huelva in Andalusia, rises in the Sierra de Padre Caro, and reaches the Huelva estuary, merging with the Odiel river.

It is not one of the longest or deepest rivers in Spain. Not even close! Read our related articles about this:

Whats The Longest River in Spain? Experts Doubt between These 2!

The Tagus River: 2 Locations, Interesting Facts and The Best Spots

Experience the Ebro River: 8 Interesting Facts, Best Spots, Beautiful Pictures and More!

5. What are the tributaries of the red river in Spain?

The Main tributaries of the Red River are the Nicoba, Jarrama, Domingo Rubio, Corumbel, Casa Valverde, and Candón rivers. To learn more about these rivers and all rivers in Spain you should visit this post:

The 34 Main Rivers in Spain + the ones no one tells you about

6. Are there fishes in the Red River?

There are no fish, vegetation, or amphibians in the Tinto River. Yet, scientists say it is overflowing with “life.” However, until very recently, it was always thought that life was impossible inside the Red River since its waters are dense and lack oxygen.

Still, the microorganisms that inhabit its waters are a challenge for science, making this river a unique place with exceptional characteristics. In the late years, analyses revealed that the conditions in which these microorganisms live correspond to a very ancient model, reproducing the environment in which life on Earth developed during the Archaic period. All this has led NASA to study the river since the life model could be similar to Mars’s life conditions. Isn’t this crazy?!!

7. Can you visit the red river?

You can visit the red river in Spain and its many attractions nearby in the municipality of Minas del Rio Tinto in Huelva.

But don’t hurry since I’ll leave you a complete guide for visiting the red river with all the activities you can do that will leave you speechless!

8. Is the red river dangerous?

You can’t bathe, swim, sail, or fish in the red river since its waters have a high level of toxicity, and this river is known to inhabit unknown life in extreme environments. However, it is worth looking for the source and stopping at the bridge just before it. There is a parking lot. The landscape has changed entirely, and the almost deserted aspect is now lush trees. There is an easy but steep descent, which requires suitable footwear, at least a pair of sneakers.

9. Why is the red river called Rio Tinto?

The word “Tinto” means that something is dark red in color and is obtained from a black grape that must be fermented with the seeds and skins of the grape. The term refers to the Red Wine, and the Red River is called Rio Tinto in Spanish due to the red color of its waters.

10. Best Activities to do in Rio Tinto

The Red River is very incredible. It is a fantastic experience worth discovering; the color of the river is actually intense red!! Also, its orange stones contrast the green pines and make it a surreal landscape. It is hard to believe that something so “extraterrestrial” can actually be found in Southern Spain!

Although it is impossible to swim in the river, there are some essential visits you cannot miss. These are:

• The Mouth of the Tinto river: It is located near the Peña del Hierro mine. Before arriving, on the left side of the road, there is a small parking lot where we can leave our vehicle. From there, after 300 meters, you’ll see the source of the Rio Tinto River.
• Las Minas de Riotinto: This is the name of this municipality that is the base of operations to visit the Mining Park of Riotinto, which contains the various points of interest and attractions that can be seen and that I will mention after.
• The Riotinto Mining Park: it offers three exciting low-cost visits: The Mining Railway, Mining Museum, and Peña de Hierro mine.

1. The Mining Railway: “A time travel through out-of-this-world landscapes” This is the perfect option if you are traveling with children or people with reduced mobility. The tour is done on a train, which you can take at the Estación Tren Turístico Minero (you can find it on the map), and the journey takes 1h 30min and will take you to Los Frailes station with a total of 11 km. 

1. The Mining Museum: it is a museum dedicated to the mining activity in the area and its history. It tells you all the history of mining in the area with more than 5000 years old, and you can see objects and reproductions of train wagons. Also, the museum building is the former mining hospital of the Rio Tinto Company Limited, which owned the Mining activities and built the railroad long ago to take the minerals to the port of Huelva. 
2. Peña del Hierro: this is an absolute must-visit if you go to Minas de Riotinto!! In the Mines of Peña del Hierro, you can enter an old mine and take a walk around the surrounding area where scientific studies of the CAB, INTA, and NASA are currently carried out to develop the Mars Project. Copper and pyrite were extracted here, then ceased to be used in 1972, and today it is a Protected Site. Today, an old gallery of more than 200 meters has been recovered, where visitors can discover the multicolored palette of a mineral-rich subsoil.

After discovering all this, if you feel like visiting some nearby towns, your route could continue to Aracena. Which is highly popular for these main things:

• Visiting the “Gruta de las Maravillas” This is a cave known for its geological formations and some subway lakes. During the guided tour, you will visit the three levels that form this cave, and it is truly a great environment to discover. 
• Trying Jabugo ham: it is considered the best acorn-fed ham and is therefore in great demand. So please remember to buy some!! It is the perfect gift for your loved ones after coming back home.
• Visiting the Aracena medieval castle: You can walk up a pleasant walk through the historic center of Aracena (although the climb has steep slopes) or take the tourist train up. The visit takes about 45 minutes and has stunning views.

For other incredible activities, I suggest you read these articles:

7 Different And Incredible Landscapes You Will Find in Spain

The 9 Best Forests in Spain to Get Lost in The Wild

11. Similar rivers in the world

Several rivers worldwide are of different colors besides the Red River. These are the following:

• Caño Cristales, in Colombia, is the famous river of the five colors. It has been recognized as “the most beautiful river in the world.” In this spectacular river, you can see colors such as; Yellow, blue, green, black, and red. This is mainly due to the presence of algae of different colors that make this river a visual wonder.
• Lake Hillier, a pink lake inside the uninhabited Middle Island in Western Australia. It is about 600 meters long and looks like an authentic bubblegum pink color from the air.
• Huang He, in Chinese or Yellow River in English, is a long body of freshwater often considered the cradle of Chinese civilization. It is the second-longest river in China, the third-longest in Asia, and the sixth-longest in the world. The unique thing about it is that depending on the year’s season, you can see this river with a yellow color.

And if you’re wondering whether this phenomenon of a river of red color happens anywhere else, then you should know that there’s another one in Peru, a Southern American country. Their Red River is known as “Yawar Mayu,” and its reddish hues can only be admired during the rainy season, which runs from November to April. The heavy rains cause the dragging of minerals, which dye the river while generating a unique and colorful spectacle along the valley.

On the other hand, in Mississippi, in the United States, there’s a river called the “Red River”, and it’s one of the main tributaries of the Mississippi River. Still, it should not be confused with the color “red” because it has blue water.

You tell me if it is worth paying a visit to this impressive river that has opened many questions for researchers, sounds like a remarkable experience, right? The most important of all this is that we value and appreciate the beautiful nature and biodiversity surrounding us. Whenever you visit any of these places, remember to follow the rules to preserve them and take care of these spaces to keep them healthy.

Let me know in the comments if you have visited the Rio Tinto, and how your experience was, we would be happy to read you!