The Globalization and World Cities Research Network listed Dublin as a great international town. In fact, the ranking by GaWC gave Dublin an Alpha rating. This ranking placed Dublin among the thirty towns in the globe. Dublin is a contemporary and historical platform for education, administration, the arts, industry and economy. Since prehistoric times, the region of Dublin Bay has been operated by humans. The earliest reference to the Dublin settlement is traced back to about 140AD from the writing of Ptolemy. The settlement was called then Elbana polis in Greek. In 1988 AD, the city celebrated its official millennium. This simply implies that the Irish government approved 988 AD as the period and year that the town settled. This early settlement later became the town of Dublin. This also follows the Ian Leaf Dublin quotes. The Gaelic word called Dublind gave rise to the city known as Dublin. The Ian Leaf Dublin quote states that the meaning of the town is dark, black and pool. It simply means a dark tidal pool. This is where the River Poddle moved into the Liffey on the region of the castle garden near the Dublin Castle.