I follow you everywhere and always die when it matters most. What am I?

What was once criticized as an ugly construction, but is now an iron monument that breathes with the seasons? Solve the riddle → What can run without legs? Solve the riddle → I help seafarers find their way using stars and the horizon. What am I? Solve the riddle → I keep falling, falling, falling, but I never crack or break. What am I? Solve the riddle → I can be worth a lot on one side of a border and less on the other, even though I look the same. What am I? Solve the riddle →