running eastward from the city's historic brandenburg gate is the unter den linden, berlin's imperial boulevard. the is the showplace of old berlin, the berlin of frederick the great, the 18th-century prussian king who commissioned many of the now-restored buildings. the name "unter den linden" means "under the lime trees." trees have always graced this boulevard except when hitler cut them down to better show off his goose-stepping army. so much of berlin is still defining itself, coming into being. it's all turmoil, excitement, and change. all over the mitte, restoration and revitalization bring berlin back to life-- like hackesche hofe, restored art deco courtyards with cafes, galleries and shops that reflect the tastes of the fashionable clientele. many of the buildings in this neighborhood have been restored to their 18th-century glory. down a side alley, i discovered an artist from the gallery monsterkabinett and, around the corner, one of their wild, mechanical creations. just another one of berlin's many hidden surprises. the mitte is also home of the reichstag: the german par