Consider a hypothetical scenario where you're tasked with designing a suspension bridge to span a wide river in a region prone to strong winds and seismic activity. Discuss in detail the key factors you would need to consider in the design process to ensure the structural integrity, safety, and durability of the bridge. Include considerations such as material selection, structural dynamics, wind and seismic loading, foundation design, and construction methods. Additionally, elaborate on how you would address potential challenges and mitigate risks associated with each factor to ensure the long$-$term functionality and resilience of the bridge under various environmental conditions.