You can thank The Spectator for the letter box
From our UK edition
A detail of daily life – scarcely noticed because it is taken for granted – was added to our houses thanks to a campaign pursued by The Spectator. I mean the letter box in the front door. In 1849, nine years after the Penny Post came in, the Postmaster General mildly suggested that time could be saved if householders were ‘to provide a letter-box, except where the outer door is kept open’. The box would function like a mailbox in America today, though a hole or slit in the door would do. In its issue of 21 July that year, The Spectator thought the recommendation ‘ought to be enforced, and might be with little difficulty. Tax every recipient of a letter living in a house which has no letter-box, by charging him an additional penny on delivery of each letter.