BA 222 then BA 478 at Heathrow
Nashville → London → Barcelona
Timetable, London time
08:50BA 222 from Nashville at the gate
08:20BA 478 to Barcelona leaves the gate
23 h 30 apart on the timetable, overnight
BA 478 leaves 23 h 30 after BA 222 arrives on the timetable: more than half a day, so not a connection we count.