Anyone who travels internationally has been affected by the changes in Unites States border security since 11 September. One dramatic change is the border between the United States and Canada, often described as the longest peaceful border in the world. Before 9/11, one could drive back and forth across the border with only a driver's license required for identification; now a passport is required. The US government is also asking foreign governments for passenger lists of all aeroplanes flying over US airspace, even if they do not land in the US (e.g. flights from Mexico to Canada). There have been radical restrictions in what you can carry on aeroplanes. Now you cannot carry a full bottle of water through security, you are restricted in the quantity of lotions and other liquids you can carry, you must remove your shoes and jacket, etc. This has resulted in long lines -- it can take over an hour simply to clear security. Similarly, on roads or bridges for the US to Canada or Mexico, long lines of traffic backed up at checkpoints are common now.