diff --git a/404.html b/404.html
new file mode 100644
index 0000000..0a6459c
--- /dev/null
+++ b/404.html
@@ -0,0 +1,12 @@
+---
+layout: home
+---
+
+<div class='container'>
+    <br />
+    <p>Oops! Page not found. Either the URL is wrong or the page doesn't exist.</p>
+
+    <p>If it doesn't exist, you can either try searching for it on <a href='https://simple.wikipedia.org'>Wikipedia</a> or writing it yourself and submitting a pull request.</p>
+
+    <p><a href="/">Go to homepage.</a></p>
+</div>
\ No newline at end of file
diff --git a/404.md b/404.md
deleted file mode 100644
index 6784181..0000000
--- a/404.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-layout: default
----
-
-Oops! Page not found.
\ No newline at end of file
diff --git a/_topic/cassandra.markdown b/_topic/cassandra.markdown
index 5bea1f1..3094ae9 100644
--- a/_topic/cassandra.markdown
+++ b/_topic/cassandra.markdown
@@ -5,4 +5,6 @@ snippet: "Cassandra is a database product used for storing very large amounts of
 website: "https://cassandra.apache.org/"
 ---
 
-Cassandra is a database product used for storing very large amounts of data. It stores the data in a similar way to an Excel spreadsheet, as a series of rows and columns. For this reason, it is often referred to as a type of "Column Store". It differs from [SQL Databases](sql) in that it doesn't allow the programmer to perform some of the more complicated types of queries that you can with SQL. This trade-off allows it to perform better when handling very large amounts of data.
+Cassandra is a database product used for storing very large amounts of data. It stores the data in a similar way to an Excel spreadsheet, as a series of rows and columns. For this reason, it is often referred to as a type of "Column Store". 
+
+It differs from [SQL Databases](sql) in that it doesn't allow the programmer to perform some of the more complicated types of queries that you can with SQL. This trade-off allows it to perform better when handling very large amounts of data.
diff --git a/_topic/computer-program.markdown b/_topic/computer-program.markdown
deleted file mode 100644
index 96ff3ae..0000000
--- a/_topic/computer-program.markdown
+++ /dev/null
@@ -1,8 +0,0 @@
----
-layout: topic
-title: "Computer Program"
-snippet: "A computer program is a set of instructions that a computer can understand and execute."
----
-
-A computer program is a set of instructions that a computer can understand and execute. These instructions are usually made up of smaller, sequential steps that manipulate information stored in the computers memory in order to fulfil the desired function.
-
diff --git a/_topic/database.markdown b/_topic/database.markdown
deleted file mode 100644
index c44c078..0000000
--- a/_topic/database.markdown
+++ /dev/null
@@ -1,9 +0,0 @@
----
-layout: topic
-title: "Database"
-snippet: "A Database is software that is responsible for storing and managing data."
-website: ""
----
-
-A Database is software that is responsible for storing and managing data.
-
diff --git a/_topic/microsoft.markdown b/_topic/microsoft.markdown
deleted file mode 100644
index a82ef7f..0000000
--- a/_topic/microsoft.markdown
+++ /dev/null
@@ -1,5 +0,0 @@
----
-layout: topic
-title: "Microsoft"
----
-
diff --git a/_topic/mobile-application.markdown b/_topic/mobile-application.markdown
deleted file mode 100644
index ea37fde..0000000
--- a/_topic/mobile-application.markdown
+++ /dev/null
@@ -1,7 +0,0 @@
----
-layout: topic
-title: "Mobile Application"
-snippet: A Mobile Application is a computer program designed to be executed on a phone.
----
-
-A Mobile Application is a computer program designed to be executed on a phone.
\ No newline at end of file
diff --git a/_topic/windows.markdown b/_topic/windows.markdown
deleted file mode 100644
index 87e749e..0000000
--- a/_topic/windows.markdown
+++ /dev/null
@@ -1,7 +0,0 @@
----
-layout: topic
-title: "Windows"
-snippet: "Window is an operating system created by Microsoft."
----
-
-Windows is an [operating system](operating-system) created by [Microsoft](microsoft).