One of the main problems in the Tel Aviv real estate scene is the lack of available building plots. As a result, Tel Aviv and its twin cities of Ramat Gan and Givatayim are building upward. In the next 10 years or so, 30,000 new apartments will be built in high-rise residential tower blocks of from 20 to 70 stories. The construction of so many new apartments will improve the supply of apartments in Tel Aviv, but it is doubtful whether it will bring down prices. Building high-rise residential complexes is very expensive. Furthermore, maintenance costs are high. Consequently, the costs of such apartments is high. The least expensive 120-sq.-m. apartments in these towers will cost at least $420,000. In the Hadar Tower project in Ramat Gan, the monthly maintenance cost is more than $250. The most expensive project to date are the planned 40-story residential towers in Tel Aviv's Kikar Hamedina. It is estimated that an average 120-sq.-m. apartment may cost $2.4 million, with monthly maintenance costs of $1,000. Currently, the most expensive apartments are in Shoftim Tower. A penthouse was sold to a local business tycoon for $13m., and there are rumors that a potential overseas client is negotiating the purchase of an apartment for $18m.