title: Why Navigation Properties are virtual by default in EF
body: <p>I have following POCO class being used in EF 6.x.</p>
  
  <p><strong>My question</strong>: Why is the navigation property of 'Posts' under 'Blog' entity declared as virtual?</p>
  
  <pre><code>public class Blog 
  {  
      public int BlogId { get; set; }  
      public string Name { get; set; }  
      public string Url { get; set; }  
      public string Tags { get; set; }  
  
      public virtual ICollection&lt;Post&gt; Posts { get; set; }  
  }
  </code></pre>