where access. The user can access the cloud or

where the users access their data and applications outside their own local computing environment through the internet. Cloud computing is defined by NIST(the US Government’s National Institute of Standards and Technology)  as “a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction”, and in a simplified way the IT researcher defined it “as a style of computing in which scalable and elastic IT-enabled capabilities are delivered as a service using Internet technologies”.The best approach to understand the cloud computing is to think of it like renting instead of buying or in more simplified it is like a utility that you use and pay for what you use.Actually, the user rents what he wants computing, network, storage and he buys only for what he used and it is a basic concept in cloud pay as you go.Cloud computing provides great benefits to the industry and business-like flexibility, scalability and transform the expenditure from CAPEX to OPEX so there is actually to move and migrate our business to the cloud and regarding 16 they review how to migrate the smart cities application to the cloud and how it benefits the smart cities to enhance the quality of the city that leads to making our life better16 and now we will discuss the main characteristics of cloud computing as follows: • On-demand self-service.  The user can be provided automatically without any human interference what he required from (for example storage, network, Bandwidth and so on..)• Broad network access. The user can access the cloud or the application ,for example, he did from any device even thin client like a laptop, mobile, personal computer.The cloud is independent of the location of whom access.• Rapid elasticity. The cloud provides the user of fully elasticity to scale up or down as he wants regarding to his business that minimize the cost and accomplish the availability of your business for example business started with some resource after short long time the business growth exponentially and the user in need of trebling the resources so he can do that in cloud in a while instead of buying it so he saves the time and the cost• Measured service.The cloud provider provides their services as measured services that facilitate the calculation and the controlling for both the provider and the user and that supports the elasticity and the scalabilityOver the past years, the term ‘smart cities’ has evolved to denote the cognitive processes combined with the deployment of ICTs, institutional settings for innovation and physical infrastructure, which taken altogether increased the problem -solving capability of a city or a community.Gathering complicated and massive data from ubiquitous sensors, people, software and devices to analyze it in real-time to get information for many reasons like healthcare, management, prediction to know the needs of the city and get the full picture is the main features of the smart cities.As we defined our heroes in the smart cities which they are IOT which enabling the city to collect the data from many sources like RFID, cars, smart houses, smart cars, etc, Cloud computing where to store and process the massive data coming from heterogeneous resources and the big hero is the big data for sure the massive data is needed cloud as storage and needs real-time processing cannot be processed using traditional ways as the 5 Vs of big data are accomplished in the smart cities data. The paper12 reviewed main reasons why the IOT is adopted in smart cities.(1)The enormous capacity that the cloud computing provides.(2) doing the complicated processing centrally(3)the ability to change of resources configuration at any time (4) dealing with IOT devices through friendly applications as we will see in the surveyed applications(5) disaster recovery options and the high speed of the networkApplications of smart citiesIn this paper we reviewed the innovative application in three disciplines which they are healthcare, smart homes and smart transportation as they will play the  great role in the smart cities so the upcoming parts in this paper are reviewing healthcare application in smart cities in  then we will move to discuss the state of the are in smart homes application in B and finally we will discuss and review the application and some architectures in smart transportation.Healthcare applicationsWith those expanding Ubiquity of recent technologies like cloud computing, smart sensors, wearable devices, smart phones and new communication technologies. Smart healthcare systems that used in remote real-time surveillance or diagnosing disease remotely become a major part of the smart cities to promote patients with qualified caring and make their life better1. The massive amount of data emerged from devices, sensors and maybe also from the citizen himself needs to be analyzed using big data analytics with cloud computing where processing and storing healthcare data. Actually designing a system that integrates and accomplish sharing between all stakeholders in smart cities like smart home, traffic, hospitals and doctors to enhance the quality of healthcare systems is a challenging mission. The governments in smart cities all over the world are trying to establish their coming healthcare systems to be smart healthcare systems by employing monitoring healthcare systems to improve their resident’s life