Запруда

1864 год, а какие линии. Не говоря уж про точность и идею конструкции.

Impressive engineering
I can't to begin to comprehend how you would build something like this - the overflow at Torside Reservoir, constructed in 1864, well before laser spirit levels, the rim of this overflow is millimeter perfect the whole way around - the lake appears to have a wedge cut clean out of it. Im guessing there was a lot of one-upmanship between reservoir designers, as most of the reservoirs around this part of the peaks have a variety of impressive overflows like this - eg the ones at ladybower reservoir that look like whirlpools