Which one of the following major world rivers traditionally had no bridges built across its main course for a very long distance due to its great width and remote surroundings?

Introduction / Context:
Some famous world rivers flow through remote dense forests or difficult terrain where building bridges is technically challenging and economically expensive. For a long time parts of these rivers had no bridges crossing their main channels. This question focuses on a particularly well known example and tests your awareness of basic world geography and unique river features.

Given Data / Assumptions:
The question tells us the following.

• We are looking for a major world river whose main course historically had no bridges over a long distance.
• The river is notable for great width and remote surroundings.
• Options include Nile, Congo river, Amazon river and Yellow river.
• Only one of these matches the popular general knowledge fact mentioned.

Concept / Approach:
The Amazon river in South America is extremely wide, flows through vast rainforest areas and has relatively low population density along many stretches. For many years it was commonly known that there were no bridges across its main channel, largely due to engineering and economic reasons. The approach is to link this widely quoted fact with the correct river. Other rivers like Nile and Yellow flow through more densely populated regions with numerous bridges.

Step-by-Step Solution:
Step 1: Recall that the Amazon river is famous for having an enormous width and length and for flowing through the Amazon rainforest. Step 2: Remember reading that historically there were no bridges over its main channel because towns are located mostly along its banks and transport relies on boats. Step 3: Consider the Nile which flows through Egypt and other countries where many bridges cross the river, especially near cities. Step 4: Note that the Yellow river in China also passes through densely populated areas with multiple bridge crossings. Step 5: Recognise that the Congo river does have some crossings but is not the classic example used in general knowledge books. Step 6: Therefore select Amazon river as the correct answer.

Verification / Alternative check:
Many general knowledge compendiums and geography trivia books state that for a long time the Amazon river had no bridges spanning its main course due to its width, flood regime and the heavy reliance on river transport. While local bridges may exist over tributaries or new construction may change the situation over time, the classic exam question reflects this well known fact. Comparing notes across several such sources supports the answer Amazon river.

Why Other Options Are Wrong:
Option A Nile passes through major urban centres like Cairo where there are several bridges connecting both sides of the river. Option B Congo river flows through central Africa and while it is challenging to cross in some parts it is not the standard textbook example for having no bridges. Option D Yellow river in China also features many bridges due to dense population and industrial development. These rivers therefore do not fit the unique feature highlighted in the question.

Common Pitfalls:
Candidates sometimes misinterpret the question and think only about river length or discharge rather than bridge construction. Others may assume that the Nile as a very long river must have segments without bridges and mark it incorrectly. Another error is to overlook how sparsely populated Amazonian regions are compared to valleys of the Nile or Yellow rivers. Keeping both physical and human geography in mind helps to avoid such mistakes.

Final Answer:
The river traditionally known for having no bridges across its main course is the Amazon river.