Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Vizcaya Bridge' has mentioned 'Iron' in the following places:
Occurrence Sentence Text Source
It was the first to use a combination of iron technology and new steel cables which began a new form of constructing bridges which was later imitated throughout the world.
The towers are braced by iron cables to the crossbeam and are parallel to the river and by cables following the line of the bridge into the hill behind (on the Portugalete side) and the ground (on the Las Arenas side).
It is made of iron.
Much iron was extracted from the mines of Vizcaya, which increased the mining and shipping industry.