This is a banknote from the hyperinflationary period of the German Weimar Republic.
https://en.wikipedia.org/wiki/Hyperinflation_in_the_Weimar_Republic
It has been used ignominiously by a carpenter as a scribbling pad.
Other countries have suffered periods of severe inflation, often when their Governments resorted to creating, and often literally printing, currency to pay their debts. Done in a measured way, such as through Quantitative Easing, it can successfully revive an economy.
https://en.wikipedia.org/wiki/Quantitative_easing
Done irresponsibly, as in Zimbabwe or Venezuela, it can result in a complete undermining of the currency. Zimbabwe essentially abandoned the Zimbabwe Dollar in 2009, and now uses the currencies of other countries, notably the South African Rand.
https://en.wikipedia.org/wiki/Zimbabwean_dollar
