As an AI language model, I do not have real-time information on the current crowd levels in Travemünde. However, you can check the current crowd levels by looking at live webcams or checking local news or tourism websites for updates on the current situation. Additionally, it's always a good idea to consider visiting during off-peak times to avoid crowds. **

It is difficult to predict exactly how crowded Phantasialand will be as it can vary depending on the day and time of year. However, it is generally a popular theme park and can get quite crowded, especially during weekends, holidays, and peak seasons. It is advisable to check the park's website or social media for updates on crowd levels and to consider visiting during off-peak times if possible to avoid long lines and large crowds. **

Gyms can vary in terms of how crowded they are on Sundays. Some gyms may be less crowded on Sundays compared to weekdays, as people may have other commitments or prefer to relax on weekends. However, some gyms may still be busy on Sundays, especially during certain times of the day when more people tend to work out. It ultimately depends on the specific gym and its location. **

Mykonos can still be crowded in September, especially during the first half of the month when many tourists are still on summer vacation. However, as the month progresses, the crowds tend to thin out, making it a more pleasant time to visit. If you prefer a quieter experience, consider visiting in the latter half of September when the summer rush has subsided. **

Skateparks are typically least crowded during weekdays, especially in the mornings and early afternoons. Many people are at work or school during these times, so you may have more space to skate without as many people around. Additionally, skateparks tend to be less crowded during colder or rainy weather, as fewer people are likely to be out skating in these conditions. **

Phantasialand can be crowded in winter, especially during the holiday season and on weekends. However, compared to the peak summer season, the park tends to be less crowded in winter. Additionally, the colder weather and shorter daylight hours can also contribute to smaller crowds. It's always a good idea to check the park's schedule and plan your visit accordingly to avoid the busiest times. **

The aquarium is not too crowded. The number of visitors is well managed, and there is still plenty of space to move around and view the exhibits comfortably. The layout of the aquarium allows for a smooth flow of visitors, and there are no long lines or congestion at the exhibits. Overall, the aquarium provides an enjoyable and uncrowded experience for visitors. **

Public transportation is typically least crowded during off-peak hours, such as mid-morning or mid-afternoon. Additionally, weekends and holidays tend to have fewer passengers, as people are not commuting to work or school. If you want to avoid crowded public transportation, it's best to plan your travel during these times. **