This is very close to the centre of Cascais and if you are in the area you must visit. I visited in November in a relatively calm day but the experience was excellent. The whole area consists of high cliffs with the large waves breaking against them - Great for photographs. To top it all however you have to visit Boca do Inferno which is a cliff arch where the waves break through creating conditions like a huge washing machine. Sometimes the best things in life are free and this is among the best that nature throws at you. I loved it.

After leaving Sintra our tour headed west reaching Portugal’s Atlantic coastline before following it south towards the estuary of the Tagus River. Just before the river reaches the ocean, we came across a natural wonder that has become a local attraction, the Boca Do Inferno or Hell Mouth. Along this part of the coast there are either long beaches or massive cliffs that the waves crash against. At this point they have over the centuries carved out a deep chasm which the water enters and recedes from in an invigorating show. Several viewing platforms and walkways allow one to get fairly close to the chasm in relative safety. As we were on a bus tour, we only made a brief stop here, but it was sufficient to thoroughly enjoy this natural wonder. As an added bonus we arrived at sunset and the always spectacular sunsets in this area made a great backdrop. The Boca Do Inferno is easy to reach from Lisbon along the costal highway that runs west along the north bank of the Tagus Estuary towards the costal resort towns of Estoril and Cascais. There is ample free parking on the site, as well as restrooms and a small souvenir shop and snack bar.

30 minute walk from train station hugging the beach takes you to this impressive rock formation. Haven for photographers - loved the plaque that paid tribute to Aleister Crowley too. Very craggy and steep staircase down to main view point. While I agree with views on stalls, we just needed an ice-cream and a cold drink before heading back into town. Worth a visit.

I knew in advance that this place is only special during storms, so I wasn't surprised that since the sea was calm when we were there, this was nothing spectacular. We had already been to other beaches in Portugal and so even though the water hitting the rocks was pretty, you can see the same thing at any other beach in Portugal and not have the same crowds. I would love to be there on a stormy day.