Ptolemy probably died before he could see the project completed, but his son and successor, Ptolemy II, is thought to have finished the job. Around 350 feet (107m) high – though that is very much an estimate – the lighthouse was probably built in three stone tiers, the first square, the second octagonal and the third round. It was a guide for visitors coming into the harbour – and a splendid tourist attraction once they had docked. A cultural, economic and intellectual symbol of the city, the lighthouse later appeared on Alexandria's coins. Writing 400 years later, Roman historian Pliny the Elder recorded that its construction cost 800 talents of silver, equivalent to around £2.4m ($3m) today.