basements, which are often used for storage. The first self-storage facility in Europe was started in the United Kingdom by Doug Hampson, and opened in central London in 1979. Called Abbey Self Storage, it would become the first self-storage chain in Europe. "... it was Doug Hampson who gave Britain the modern self-storage industry, with its bright, clean corridors and endless rows of brightly-coloured doors. In the industry he is widely credited with the enviable title of the "father of UK self-storage". Modern storage facilities grew slowly through the '90s, at which time demand outpaced supply and caused a rush of new self-storage developments. From 2000 to 2005, over 3,000 new facilities were built every year in America. Self storage today At year-end 2019, there were 47,539 self-storage facilities in the United States on industrial and commercial land parcels. There is more than 1.9 billion square feet of available self-storage in space in U.S. The six largest publicly traded storage operators (four REITs, and U-Haul own or operate approximately 18% of self-storage facilities. The global industry was worth 48.02 billion U.S. dollars in 2020. More recently, in many metropolitan cities where competition among storage companies is fierce, better parcels of land near residential and commercial areas are being converted into self-storage once approved by zoning panels. Companies are becoming more adept at manufacturing these modular storage units, allowing operators to get up and running quickly. To support the need, businesses like PODS are expected to enter the modular construction effort as well. Mailstorage or on-demand storage is where customers' items are kept together in a warehouse rather than providing each customer with a storage unit. Self-storage businesses lease a variety of unit sizes to residential and business customer/tenants. Popular unit sizes (with width shown first and depth shown second) include: , about the size of a large Telephone booth , about the size of a large walk-in closet, , about the size of a child's bedroom (as of 2015, 10x10's are the most common storage unit size, making up 16% of the distribution in the U.S.), , about the size of a living room, , about the size of a one-car garage, , about the size of a large master bedroom, and , about the size of a two-car garage. The storage units are typically window-less, walled with concrete cinder blocks or corrugated metal, and lockable by the renter. Each