The back of the Tower of Terror has always been visible from inside the park. I agree it's not the most beautiful sight, but it's not a plain tall wall either. It has some windows and very subtle ornaments at the top and vertical stripes running from top to bottom. From the likeside of Arendelle, the TOT will be quite far. It will be visible, of course, but I don't think it's going to be a big problem. From the ground perspective, the trees will block the view in many places. Our eyes will focus more on the Regal view restaurant and the East pavilion building.
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As a reference, this is the Google maps view from the berm. A small tree is enough to completely block the view of the tower. In the lake, the distance will be aprox half of the distance from the berm, so a larger tree might be needed, but still will be able to block the view from many places.
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