Hi!we are planning to have a 4 day vacation this dec 2009...since we have valid passport, we no longer need hongkong and macau visa, right? what if we decided to go to shenzen even for just a day, do we need to apply for shenzen visa? aside from that my companions are still classified as children because they're just 15 years old, but im already 25, do they need to prepare other documents aside from passport? thank you!