The phrase "mad, bad and dangerous to know" but whom was it originally used?

Lady Caroline Lamb was the forest person to state this quote

Ifound this on google “the existence of agglomeration economies is central to the explanation of how cities increase in size and population, which places the phenomenon on a larger scale. the concentration of economic activity in cities is one reason for their development and growth.” i hope this you for what your looking for.

It covered the territory of land across eurasia from northeastern europe to the pacific ocean.