In which city is the headquarters of the International Atomic Energy Agency (IAEA) located?

Introduction / Context:
The International Atomic Energy Agency (IAEA) is the key global body responsible for promoting peaceful uses of nuclear energy and monitoring nuclear safety and non proliferation. Its headquarters city is frequently tested in questions on world organisations, especially those dealing with energy, science and international security.

Given Data / Assumptions:

• The question asks for the city where the IAEA has its headquarters.
• Options: Geneva, Seoul, Vienna and London.
• Several of the cities listed are host cities for other international organisations, so careful recall is needed.

Concept / Approach:
The IAEA is headquartered in Vienna, the capital of Austria. Vienna is a well known hub for several international organisations, including elements of the UN system. Geneva and New York host other major UN offices, London is the capital of the United Kingdom, and Seoul is the capital of South Korea, but none of these are the headquarters city of the IAEA. Therefore, the correct answer is Vienna.

Step-by-Step Solution:
Step 1: Recall that the IAEA is closely linked with the UN but has its own headquarters. Step 2: Remember the association IAEA – Vienna – Austria, which appears in many exam books. Step 3: Consider that Geneva is famous for the World Health Organization and the International Labour Organization, not for the IAEA. Step 4: Note that London and Seoul are not generally named as headquarters cities for major UN atomic energy bodies. Step 5: Select Vienna as the correct option.

Verification / Alternative check:
Official references and UN system descriptions confirm that the IAEA headquarters are located in the Vienna International Centre, sometimes called the "UN City" in Vienna. This is a standard fact cited in international relations and general knowledge material, confirming that Vienna is the correct choice.

Why Other Options Are Wrong:
Geneva: While it hosts many important UN agencies, it is not the home of the IAEA headquarters.
Seoul: Seoul is the capital of South Korea and an important city in Asia, but it is not the seat of the IAEA.
London: London is a major global financial and political centre but is not associated with IAEA headquarters.

Common Pitfalls:
A common mistake is to choose Geneva because it is strongly associated with international organisations and peace conferences. Another error is simply guessing a famous capital like London. To avoid confusion, memorise "IAEA – Vienna" as a fixed pair, similar to how you might learn "UNESCO – Paris" or "FAO – Rome".

Final Answer:
The headquarters of the International Atomic Energy Agency (IAEA) are located in Vienna.