I want to know the answer to the following question:
What artificial geological feature was added to Seattle in 1909?
All the background I'm provided with is that "The topography of the city center was also changed by the construction of a seawall and the artificial Harbor Island (completed 1909) at the mouth of the city's industrial Duwamish Waterway, the terminus of the Green River.". Is that enough to answer the question?
Answer: yes