| It's quite hard to think of a city that doesn't have a big river running through it. |
| If you think about the major cities in the world, |
| Shanghai, New York, Mumbai, London, |
| they're nearly all built on rivers. |
| When these cities were established hundreds or even thousands of years ago, |
| the rivers were a big part of people's lives. |
| In 16th century London, the quickest way to get from one part of the city to another was by river. |
| But people also used the river for fishing as the water then was relatively clean, |
| and they would also go on boat trips up and down the river just for pleasure |
| as a relaxing escape from the noise and bustle of the city streets. |
| But as industries developed and populations increased city rivers suffered. |
| The rising number of people meant there was a huge increase in the amount of sewage discharged into the rivers. |
| Rivers had always been used for this purpose, |
| but when the number of inhabitants was so small, that wasn't such a problem. |
| However, as cities grew to over a million inhabitants, |
| the impact on the rivers became more serious. |
| In addition, other types of pollution increased, |
| as factories were built beside the river and discharged their waste materials into the water. |
| This got worse over time. |
| As recently as 1957, |
| scientists at London's Natural History Museum declared that the River Thames was dead in biological terms, |
| as the water was too filthy to support any kind of life. |
| But in recent years, as rivers lost their industrial function, |
| cities have begun to recognise their true value and to take steps to clean them up. |
| For example, the River Thames is now cleaner than it's been for 150 years. |
| These days you can see seals swimming in the water, |
| and recently people had to try to rescue a whale, which had got lost and swam up the river from the sea by mistake. |
| Unfortunately, they didn't succeed, |
| but the problem was disorientation rather than the quality of the water. |
| Then, all around the world, riverside areas are now seen as prime sites for development. |
| Warehouses that were once used for storing goods are now being converted into expensive restaurants |
| and also into apartments with river views, which are in great demand and sell for astronomical prices. |
| In Los Angeles, on the west coast of the USA, an architect has plans to revitalise the banks of the river |
| and to make a park there which can provide facilities for sports as well as a natural environment for relaxing in. |
| It's also hoped that the riverside can be used for other purposes. |
| It's been proposed that facilities could be provided for displaying projects related to various kinds of art |
| that have been produced by local people, for example. |
| In the city of Paris, during the summer months of July and August, |
| all the traffic is banned from the roads by the sides of the river, |
| and the banks are transformed into beaches, |
| where people can relax in deck chairs under potted palm trees, |
| sunbathe or buy a drink or a snack while enjoying the view. |
| But to make the most of our rivers in our increasingly crowded cities, |
| we need to allow them to regain their original purpose and be used as a means of transport, |
| reclaiming our streets from cars and lorries. |
| To do this, we'll have to shift more traffic back to the river, |
| but this time cleanly and silently, making the most of modern technology. |
| Already, more than two billion passengers use the ferry to travel in cities around the world, |
| like Istanbul, San Francisco and New York, |
| and these numbers are set to rise further. |
| Admittedly, it's not a fast way of travelling, |
| but neither is a car when it's stuck in traffic. |
| Of course, passenger traffic on roads might decrease as more people start working from home, |
| but another recent development, the huge rise in online shopping, |
| has meant that another form of urban traffic just keeps on growing, |
| and that's deliveries. |
| Trucks and vans in the city pollute and double-park while dropping off parcels. |
| Imagine using the immense capacity of shipping to take these trucks off the road. |
| One freight barge can replace 44 large trucks, uses far less energy and causes less pollution. |
| When the barge docks at the riverside, |
| the parcels could be taken the last few kilometres to their final destination on cargo bikes, electric ones of course. |
| This is already happening in the Dutch city of Amsterdam, |
| and in future, the final stage could even be carried out by drone, |
| although at present this isn't allowed. |
| Wouldn't it be great to unblock our city centres in this way? |
| Looking further ahead... |