There are many sites in Second Life that are either repesentations of Real Life historical places, or that are fictional representation of history.  You'll find some of each below!

Greece Official (Mature--but site requests no nudism or offensive behavior)

The official (whatever that means!) sim of Greece.  I'm not entirely clear if this is really through the Greek government, but it does have a very good recreation of the Parthenon in Athens, a nice Greek theater, and even a nice modern soccer stadium! 

http://slurl.com/secondlife/GreeceOfficial/60/93/39/

Roma (Mature--justified in some areas, but still great!)

Roma is an entire sim with an ancient Rome theme.  Very detailed and creative, with shopping, gladatorial training, an arena, a palace, and much more.  The perfect sim for history buffs. 

http://slurl.com/secondlife/ROMA/214/25/22

Chichen Itza (Mature, but seems PG)

A sim that recreates one of the wonders of the ancient "New" World.  The full pyramid is recreated, along with some associated temples.   This site is run by the Mexican tourism board.

http://slurl.com/secondlife/Visit Mexico/198/69/38/