Answer:
The Fearless Five infiltrated the Trippenhuis Museum in Amsterdam, Netherlands.
Explanation:
The Trippenhuis Museum that is situated in Amsterdam, the Netherlands, is one of the world's most famous museums. The painting named 'The Night Watch' mentioned in the question is the main attraction of this musueum. The painting was made by the Dutch painter named Rembrandt van Rijn who is regarded as the greatest figure in the history of Dutch visual art.