People have been taking coach trips to Barcelona for a few decades now but the city started its life a few years before this. There are two different legends that the foundation of Barcelona is the subject of. The first attributes the founding of the city to the mythological Hercules, 400 years before the building of Rome. The second attributed the foundation of the city directly to the historical al Carthaginian Hamilcar Barca, father of Hannibal, who named the city Barcino after his family, in the 3rd century BC. Around 15 BC, the Romans used the city as a military camp centred on a little hill by the current city hall. It is mentioned as one of the smaller towns of the district in Mela, but it gradually grew in wealth and became favoured as it was in a beautiful location and had an excellent harbour. The city minted its own coins, and some of them from the era of Galba (the sixth Roman Emperor) have survived. Some important roman ruins still exist today and are exposed under the Placa del Rei entrance by the city museum, and the typical roman grid planning is still visible in the layout of the historical centre, the gothic quarter. Some of the remaining fragments of walls have been incorporated into the cathedral. The city was conquered by the Visigoths in the early fifth century and Barcelona temporarily became the capital of the whole Hispania. After that the Arabs took over in the early eighth century, but Barcelona was reconquered again in 801 by Charlemagne's son Louis, who made Barcelona the seat of Carolingian, a buffer zone ruled by the Count of Barcelona. The counts of Barcelona became increasingly independent and expanded their territory to include the whole of Catalonia. Barcelona then merged with Aragon to and was known as 'The Crown of Aragon', which ruled the western Mediterranean sea. A dynastic link between the crowns of Aragon and Castile was forged and this marked the beginning of Barcelona's decline. The centre of political power became Madrid and the Americas ruled the financial importance of Mediterranean trade. Barcelona was always the stronghold of Catalan separatism and was the centre of the Catalan revolt against Philip IV of Spain. The great plague of 1650-1654 halved the city's population, and the Napoleonic wars left the province ravaged, but the post-war period saw the start of industrialisation. Today Barcelona remains the second largest city in Spain which is relatively industrialised. It retains the however, the reputation of Spain's most happening city, and seems set to remain that way.