 my talk is about retrofitting. That is when we have a very high density city and a lot of people are pretty resigned thinking that we cannot do much about increasing the greening or improving the greening but my study is trying to prove otherwise. I try to tell people that even though the city is highly compact, you can still find some spaces for greening. So we begin with Hong Kong, which is an extremely dense city with only 25% built up because of the very rugged topography. We have to refine our urbanization to a very small area. And as a result, the density is extremely high. So my purpose is to find potential greening sites, PGS, where you have a high density city. So I'm trying to give hope to people that even in a very cramped area, you can still find spaces here and there to green. So what we find is not just restricted to the ground level. I also look at the so-called three dimensional greening, the green wars and the grooves. So I hope this can serve as a pilot study or a demonstration project to tell people in other cities and other districts that urban greening can still be improved despite the extremely high development density. So I use Chun-Wan Yutang as my study area, which was developed as early as the 1950s. So it's almost 70 years old and is really getting aging. And by the way, the mode of development of Chun-Wan is very similar to the old city and that is everything is crammed together. So I divided this city into nine neighborhoods, neighborhoods with similar land use and characters. And then I begin to send my team of research assistants to search for the potential greening sites. I look at the dimension, the location and environment and then I assess each site very carefully so that I can make specific recommendations as to what can be planted there. And I also took efforts to refurbish some of the existing sites where the greenery is of a poor quality. Now I begin by building up a GIS database and then manage it with Archinfo to make sure that my data is systematic and well organized. And all together I identify more than 600 sites in the time. So you can see that this is the database that I have built up. And then I try to use also photos, use remote sensing to identify and measure the so-called vacant roof sites and vacant podium platform sites to, so to speak, identify all the above ground horizontal spaces that are at present not vegetated. And I use the polygons to measure that. And then I begin to build up my so-called landscape retrofitting plan. My plan here is mainly focusing on the above ground part. It does not mean that the ground level part is not important, but due to the limitation of time, I focus on the three-dimensional greening. And these are the sites that we can use, footbridge, wall, column, roof and podiums, and the pedestrian shelters and the fences. I begin by looking at the footbridges. The Chin-Wang New Town is renowned for its proliferation of footbridges everywhere. And unfortunately a lot of these footbridges are bare and they are wonderful sites for greening because of their three-dimensional feature. So I classify them into six types and then I try to introduce different kinds of vertical greening methods. Other than making use of the existing planters, I use wire root method and wire mesh methods to include them. Of course, I have identified these suitable sites where you have enough sunshine and the appropriate structure to support vertical greening. This is just one example of a circular footbridge which will be planted with beautiful flowering climbers. And then I also look at the walls, different kinds of walls. I classify them into four types and then I try to use two versions of vertical greening. First is the self-climbing type. Some climbers can move up the wall without support and the others will need some kind of support or training system such as wire mesh and wire rope. And here I have a good example of a pretty large blank wall on the private building and I intend to green it with a very nice flowering climber called the Rangoon Creeper. And I hope many more walls in the city in the town can be green in this manner. And then we have the retrofitting plan for the columns. Now Chun-Wan Liu Chang is also famous for his numerous flyovers for vehicles and these flyovers have big and tall columns which at present are mainly blank. I like to green them beautifully again with climbers of different kinds using the methods I would introduce for the green walls. And here is a good example of a column. The green I would try to use the soil in the ground rather than use planters if it is possible. And then I use the roofs. There are numerous vacant roofs in Chun-Wan town because it is previously in an industrial town where you have very large footprint industrial buildings and the floor loading of these buildings are very high. So I can introduce not just a basis or a ground cover vegetation. I can introduce even sky woodlands on them. And here is a good example of the roof of an indoor market with a high floor loading. And I propose to set up a community farm on it instead of an existing playground which is highly used. And then I look at the podium. In Hong Kong, many buildings have a podium above the so-called parking or shopping levels. And this podium is similar to roof can be greened in many ways. So I use the same method as the roofs to green them. I mainly select the flowering vegetation to introduce more beautiful plants. And then here is a good example of a podium where if it is possible, I even introduce some medium-sized trees to decorate them. And then we have the shelter. In the town, we have many shelters for pedestrians to wait for buses and minibuses, taxi and so on. And these shelters are wonderful opportunities for above ground greening. So I divide them into four main types and again use the vertical greening methods to green them. And here you have a good example of a little shelter where people wait for minibuses and it will be green to provide cool shade and beautiful flowers. And lastly, we have the fences. Hong Kong is probably the most fenced city in the whole wide world. You have fences everywhere, but most of these fences are bare. So why not make use of them to provide some mini-scale vertical greening using wire mesh or some existing structures? So here you have some examples. Before and after. So here are some very fine examples of how we can introduce lots and lots of greenery into the city. Even though it is apparently rather hopeless in terms of the opportunities for further greening. Thank you.