Using br for line breaks:

Listen, my children, and you shall hear
Of the midnight ride of Paul Revere,
On the eighteenth of April, in Seventy-Five:
Hardly a man is now alive
Who remembers that famous day and year.

Line breaks and spaces in HTML code don't render...(exception below):

Listen, my children, and you shall hear Of the midnight ride of Paul Revere, On the eighteenth of April, in Seventy-Five: Hardly a man is now alive Who remembers that famous day and year.

...except in the "pre" (preformatted) element:

Listen, my children, and you shall hear
    Of the midnight ride of Paul Revere,
On the eighteenth of April, in Seventy-Five:
    Hardly a man is now alive
Who remembers that famous day and year.