Vertical and Horizontal Straighten
This image is taken with a fisheye lens:
                                    
									5 vertical curves are added. Only the first curve from the left has 2 Curve Segments:
                                    Vertical Straighten is performed and "Set to Initial Width x Height Ratio", the result is:
                                    Let us do a Horizontal Straighten. Add the first Horizontal curve at the top of the image. Try to accomplish a curve shape nearest to the curvature of the right beige building:
                                    Set the number of Curve Segments to 4 and reshape the curve like this:
                                    Add new Horizontal curve and set their shape like this:
                                    Move down the last curve:
                                    Duplicate curve (press Command D):
                                    Change Curve Segments to 3:
                                    Set curve with 3 Curve Segments:
                                    We will use the first curve with 3 Curve Segments from the bottom to fine reshape:
                                    This is one of a few steps:
                                    Reshaping is finished. Select a curve with 1 Curve Segment and delete it by clicking "-" (hint: Delete Horizontal Straighten Curve). Now, the curve shape looks like this:
                                    There are 3 new Horizontal curves in these positions:
                                    These 3 new curves are with 3 Curves Segments.
                                    After Horizontal Straighten and "Set to Initial Height x Width Ratio", the image looks: