Brain › WorldIn what decade were the first commercial Valentines cards produced in the United States?1920s1870s1840s1930sAnswerThe correct answer is C) 1840s.More World questionsWhich country governs Christmas Island?Where is the Easter Island located?Which of these rivers is considered sacred in Hinduism?On which island did Napoleon die?Which part of the US is known as the Bible Belt?Which capital city name can be translated as God-given (or Gods gift)?Play Brain · Practice