How the city of London became the world's richest Square Mile [is? Why?]

The evolution of London as the wealthiest square mile globally and the factors driving its financial success.

Overview:
London, a historic financial hub within greater London, stands as the globe's most prosperous square mile. Anchored by institutions like the London Stock Exchange, it wields significant economic might and sway, bolstering the UK's GDP. The city's opulence traces its roots to Roman times, expanding over centuries through trade, business, and its strategic positioning..