I thought it would be cool to make a list of Monasteries/Centers with great reputations and that are examples of intensive practice.
Additional benefits we get to learn from each other, know places to support for positive karma, and learn about excellent teachers.
Ones I can add to the list:
I wish I could add more from Mahayana but I am not knowledgeable enough
Ajahn Chah monasteries are great because when staying one has a lot of free time to do an individual practice and yet a lot of time also for group meditation (morning and evening) and one or twice a week staying up till midnight or all night in a meditation practice based on the moon calendar.
Sayadaw U Pandita's Panditãrãma Center is incredible for intensive mindfulness practice as described and teached by the legendary Mahasi Sayadaw.
Venerable Pa-Auk has his Forest Monastery which is very intense and based on heavy Jhana practice. (I have known a monk or two that visited there and thought the experience very beneficial.
Insight Meditation Society is a great place for intensive practice with varying teachers.