Peruvian firefighters largely controlled wildfire near the Incan ruins of Machu Picchu on Friday, though remained alert for a possible resurgence of the blaze due to strong winds near the ancient city high in the Andean mountains.

The fire, which had engulfed an area of some 30 hectares (74 acres), or over half the size of Vatican City, was started on Tuesday by farmers burning grass and debris to prepare to sow new crops.

The ministry of culture said late on Thursday that the fire had been 90% extinguished and that the incident had not affected tourist activity in the region.

The difficult access to the mountainous area had hampered the efforts of firefighters.

The risk management office of the Civil Defense Institute said in a statement that some 70 people, including firefighters, police and experts, had worked to stop the fire and that a team remained in the area on Friday on alert.

Machu Picchu, a complex of stone structures sitting atop a mountain, was built more than 500 years ago by the Incas, whose empire controlled large swaths of South America from what is today southern Ecuador to central Chile.

The breathtaking ruins, which have made the surrounding Cusco region Peru’s top tourist destination, are considered one of the new seven wonders of the world.