I think this would be the Great Wall of China!
although it's actually thought to be much, much longer: over 5000 miles long, if yoiu include natural defensive barriers used in it.
The correct answer is - dunes.
The dunes, or sand dunes, are a relief forms that are formed by deposition of material. In the process of forming a dune, the responsibility goes to the eolian processes (wind processes). The wind has its own mechanical power to erode the rocks, but it also has the power to transport the material. The stronger the wind, the bigger the particles it can transport, and vice versa. When the wind is transporting a certain material, in the case of the dunes it will be sand particles, eventually it will start to lose on speed, and as it loses on speed, it loses on power, so the sand particles are starting to fall on the ground and deposit. s more and more sand particles are depositing, the dune starts to form, and it is growing bigger as more sand particles are falling on it.
1, I want to say in the mid atlantic.
2. you use the scale on the bottom left to answer so it 1cm=405km.
3. I think you pick a line on the picture and that's the age, but I'm not to sure because I don't see a key. I hope this helps.
They used maps and are both extremely detailed to perfection
Leo da Vinci did both