That's How It Happened

While enjoying a White Lady at the Savoy last night, I mused over where else you'd have to visit to try the "original" of each of the classic cocktails. I've got some way to go on these:
Singapore Sling: The Long Bar at Raffles (tick)
Mai Tai (and the Zombie): Trader Vic's (tick)
Bellini: Harry's Bar in Venice
Mint Julep: At the Kentucky Derby
Daiquiri: Grand Hotel, Havana
Cosmo: Rainbow Rooms, Manhattan
Margarita: unknown, but presumably Acapulco
Any other suggestions? I think the origins of the Manhattan are lost in time, and obviously the Martini is claimed all over. I suppose you could order a shaken-not-stirred Martini at the Monte Carlo Casino, and feel reasonably authentic.