I'm from England...

1966 Football World Cup Winners - Our Biggest achievement.
2003 Rugby World Cup Winners.
Manchester United, Liverpool, Nottingham Forrest and Aston Villa have won the Champions League.
Steven Redgrave winning 5 consecutive gold medals at the Olympics.
Multi-5/6 Nations winners.
Semi-Finalists at Euro 64, 96 and Italia 90.
Several Ashes victories over the Aussies.
Beating Germany 5-1 in Munich.
Damon Hill, Graham Hill, Nigel Mansell, Jim Clark, Jackie Stewart, John Surtees, Mike Hawthorn all have won the F1 Drivers title.
Kelly Holmes at the 2004 Olympics.

I could go on for a long time, so I'll stop there