A giant has taken up temporary residence on the south bank of the River Thames in London. You won't miss him. He sits there looking over the water and he has made up his mind that this is the place for him. And when a giant makes up his mind about something, there is no arguing. His name is Blockhead. He is big, black and friendly. He has a massive square head, a long round nose, a gaping hole for a mouth and is 35 metres tall. If he had four identical brothers and they stood on each other's shoulders, they would reach the top of the Hong Kong and Shanghai Bank. Big is too small a word to describe Blockhead. He sits in the front yard of the Tate Modern art gallery opposite Saint Paul's Cathedral. If he stood up, he would be much taller, but he prefers to sit and take the weight off his feet. He doesn't know which city he is going to visit next. There are so many places he would like to see before he settles down. Blockhead is already a firm favourite with London tourists. He likes them and they like him. He feels very proud when everyone stops and looks up at him. There is even an opening between his feet leading into a cave where they can buy special black candy sticks. Blockhead is a people-friendly giant. He wants everybody to remember him once they have met him. Our welcoming giant is an inflatable sculpture made out of plastic and air. He was designed and put together by American artist Paul McCarthy. Blockhead is the world's largest inflatable balloon. He looks solid and heavy at the moment, but at the end of his stay at the Tate Modern, he will be deflated, packed away and moved somewhere else. Blockhead knows that he is only a temporary giant, but this does not worry him at all. Centuries ago, the Colossus of Rhodes, one of the Seven Wonders of the World, stood at the edge of Rhodes harbour, welcoming travellers to the city. Today, Blockhead is doing the same job. He is welcoming visitors to England's capital city. Blockhead is about six-and-a-half metres taller than the Colossus of Rhodes, but he likes to keep that information to himself. He doesn't like to brag about being the Colossus of London.