[emilssolmanis]

Slaves, lots and lots of slaves, many of whom died. Exactly as you'd imagine something of epic proportions being made in the 19th century.

[Clewza313]

It was built with corvee labor, which is not quite the same thing: unpaid, yes, but done by farmers etc as a form of taxation in kind.

[arwineap]

Taxation imposed by the state, but I haven't been able to find any citation of a tax code so to speak.

It seems like state sponsored slavery, without a trade. That is no persons are being sold because they are simply using citizens

Brutal.

[EricE]

Oh come now, governments can’t impose slavery - it was just taxation after all /s

[mannerheim]

Slavery doesn't have to do with whether it was paid or not (many slaves have historically been paid as well) but rather the voluntariness of their work.